QByteArray

概要

函数

静态函数

详细描述

PySide.QtCore.QByteArray class provides an array of bytes.

PySide.QtCore.QByteArray can be used to store both raw bytes (including ‘0's) and traditional 8-bit ‘0'-terminated strings. Using PySide.QtCore.QByteArray is much more convenient than using const char * . Behind the scenes, it always ensures that the data is followed by a ‘0' terminator, and uses 隐式共享 (写入时拷贝) 以缩减内存使用量和避免不必要的数据拷贝。

除了 PySide.QtCore.QByteArray , Qt also provides the PySide.QtCore.QString 类以存储字符串数据。对于大多数目的, PySide.QtCore.QString is the class you want to use. It stores 16-bit Unicode characters, making it easy to store non-ASCII/non-Latin-1 characters in your application. Furthermore, PySide.QtCore.QString is used throughout in the Qt API. The two main cases where PySide.QtCore.QByteArray is appropriate are when you need to store raw binary data, and when memory conservation is critical (e.g., with Qt for Embedded Linux).

One way to initialize a PySide.QtCore.QByteArray is simply to pass a const char * to its constructor. For example, the following code creates a byte array of size 5 containing the data “Hello”:

ba = QByteArray("Hello")
										

Although the PySide.QtCore.QByteArray.size() is 5, the byte array also maintains an extra ‘0' character at the end so that if a function is used that asks for a pointer to the underlying data (e.g. a call to PySide.QtCore.QByteArray.data() ), the data pointed to is guaranteed to be ‘0'-terminated.

PySide.QtCore.QByteArray makes a deep copy of the const char * data, so you can modify it later without experiencing side effects. (If for performance reasons you don't want to take a deep copy of the character data, use QByteArray.fromRawData() instead.)

Another approach is to set the size of the array using PySide.QtCore.QByteArray.resize() and to initialize the data byte per byte. PySide.QtCore.QByteArray uses 0-based indexes, just like C++ arrays. To access the byte at a particular index position, you can use operator[](). On non-const byte arrays, operator[]() returns a reference to a byte that can be used on the left side of an assignment. For example:

ba = QByteArray()
ba.resize(5)
ba[0] = 'H'
ba[1] = 'e'
ba[2] = 'l'
ba[3] = 'l'
ba[4] = 'o'
										

For read-only access, an alternative syntax is to use PySide.QtCore.QByteArray.at() :

for i in range(0, ba.size()):
    if ba.at(i) >= 'a' and ba.at(i) <= 'f':
        print "Found character in range [a-f]"
										

PySide.QtCore.QByteArray.at() can be faster than operator[](), because it never causes a deep copy to occur.

要一次提取多个字节,使用 PySide.QtCore.QByteArray.left() , PySide.QtCore.QByteArray.right() ,或 PySide.QtCore.QByteArray.mid() .

A PySide.QtCore.QByteArray can embed ‘0' bytes. The PySide.QtCore.QByteArray.size() function always returns the size of the whole array, including embedded ‘0' bytes. If you want to obtain the length of the data up to and excluding the first ‘0' character, call qstrlen() on the byte array.

After a call to PySide.QtCore.QByteArray.resize() , newly allocated bytes have undefined values. To set all the bytes to a particular value, call PySide.QtCore.QByteArray.fill() .

To obtain a pointer to the actual character data, call PySide.QtCore.QByteArray.data() or PySide.QtCore.QByteArray.constData() . These functions return a pointer to the beginning of the data. The pointer is guaranteed to remain valid until a non-const function is called on the PySide.QtCore.QByteArray . It is also guaranteed that the data ends with a ‘0' byte unless the PySide.QtCore.QByteArray was created from a raw data . This ‘0' byte is automatically provided by PySide.QtCore.QByteArray and is not counted in PySide.QtCore.QByteArray.size() .

PySide.QtCore.QByteArray provides the following basic functions for modifying the byte data: PySide.QtCore.QByteArray.append() , PySide.QtCore.QByteArray.prepend() , PySide.QtCore.QByteArray.insert() , PySide.QtCore.QByteArray.replace() ,和 PySide.QtCore.QByteArray.remove() 。例如:

x = QByteArray("and")
x.prepend("rock ")         # x == "rock and"
x.append(" roll")          # x == "rock and roll"
x.replace(5, 3, "&")       # x == "rock & roll"
										

PySide.QtCore.QByteArray.replace() and PySide.QtCore.QByteArray.remove() functions' first two arguments are the position from which to start erasing and the number of bytes that should be erased.

When you PySide.QtCore.QByteArray.append() data to a non-empty array, the array will be reallocated and the new data copied to it. You can avoid this behavior by calling PySide.QtCore.QByteArray.reserve() , which preallocates a certain amount of memory. You can also call PySide.QtCore.QByteArray.capacity() to find out how much memory PySide.QtCore.QByteArray actually allocated. Data appended to an empty array is not copied.

A frequent requirement is to remove whitespace characters from a byte array (‘n', ‘t', ‘ ‘, etc.). If you want to remove whitespace from both ends of a PySide.QtCore.QByteArray ,使用 PySide.QtCore.QByteArray.trimmed() . If you want to remove whitespace from both ends and replace multiple consecutive whitespaces with a single space character within the byte array, use PySide.QtCore.QByteArray.simplified() .

If you want to find all occurrences of a particular character or substring in a PySide.QtCore.QByteArray ,使用 PySide.QtCore.QByteArray.indexOf() or PySide.QtCore.QByteArray.lastIndexOf() . The former searches forward starting from a given index position, the latter searches backward. Both return the index position of the character or substring if they find it; otherwise, they return -1. For example, here's a typical loop that finds all occurrences of a particular substring:

ba = QByteArray("We must be <b>bold</b>, very <b>bold</b>")
j = 0
while (j = ba.indexOf("<b>", j)) != -1:
    print "Found <b> tag at index position %d" % j
    ++j
									

If you simply want to check whether a PySide.QtCore.QByteArray contains a particular character or substring, use PySide.QtCore.QByteArray.contains() . If you want to find out how many times a particular character or substring occurs in the byte array, use PySide.QtCore.QByteArray.count() . If you want to replace all occurrences of a particular value with another, use one of the two-parameter PySide.QtCore.QByteArray.replace() overloads.

QByteArrays can be compared using overloaded operators such as operator<(), operator<=(), operator==(), operator>=(), and so on. The comparison is based exclusively on the numeric values of the characters and is very fast, but is not what a human would expect. QString.localeAwareCompare() is a better choice for sorting user-interface strings.

For historical reasons, PySide.QtCore.QByteArray distinguishes between a null byte array and an empty byte array. A null byte array is a byte array that is initialized using PySide.QtCore.QByteArray ‘s default constructor or by passing (const char *)0 to the constructor. An empty byte array is any byte array with size 0. A null byte array is always empty, but an empty byte array isn't necessarily null:

QByteArray().isNull()          # returns true
QByteArray().isEmpty()         # returns true
QByteArray("").isNull()        # returns false
QByteArray("").isEmpty()       # returns true
QByteArray("abc").isNull()     # returns false
QByteArray("abc").isEmpty()    # returns false
										

All functions except PySide.QtCore.QByteArray.isNull() treat null byte arrays the same as empty byte arrays. For example, PySide.QtCore.QByteArray.data() returns a pointer to a ‘0' character for a null byte array ( not a null pointer), and PySide.QtCore.QByteArray.QByteArray() compares equal to PySide.QtCore.QByteArray (“”). We recommend that you always use PySide.QtCore.QByteArray.isEmpty() and avoid PySide.QtCore.QByteArray.isNull() .

区域设置注意事项

数字字符串转换

Functions that perform conversions between numeric data types and strings are performed in the C locale, irrespective of the user's locale settings. Use PySide.QtCore.QString to perform locale-aware conversions between numbers and strings.

8 位字符比较

PySide.QtCore.QByteArray , the notion of uppercase and lowercase and of which character is greater than or less than another character is locale dependent. This affects functions that support a case insensitive option or that compare or lowercase or uppercase their arguments. Case insensitive operations and comparisons will be accurate if both strings contain only ASCII characters. (If $LC_CTYPE is set, most Unix systems do “the right thing”.) Functions that this affects include PySide.QtCore.QByteArray.contains() , PySide.QtCore.QByteArray.indexOf() , PySide.QtCore.QByteArray.lastIndexOf() , operator<(), operator<=(), operator>(), operator>=(), PySide.QtCore.QByteArray.toLower() and PySide.QtCore.QByteArray.toUpper() .

This issue does not apply to QStrings since they represent characters using Unicode.

另请参阅

PySide.QtCore.QString PySide.QtCore.QBitArray

class PySide.QtCore. QByteArray
class PySide.QtCore. QByteArray ( arg__1 )
class PySide.QtCore. QByteArray ( arg__1 )
class PySide.QtCore. QByteArray ( size , c )
参数:

Constructs an empty byte array.

构造副本为 other .

This operation takes constant time , because PySide.QtCore.QByteArray is 隐式共享 . This makes returning a PySide.QtCore.QByteArray from a function very fast. If a shared instance is modified, it will be copied (copy-on-write), taking linear time .

另请参阅

PySide.QtCore.QByteArray.operator=()

Constructs a byte array initialized with the string str .

PySide.QtCore.QByteArray makes a deep copy of the string data.

Constructs a byte array of size size with every byte set to character ch .

PySide.QtCore.QByteArray. __getitem__ ( )
PySide.QtCore.QByteArray. __getslice__ ( )
PySide.QtCore.QByteArray. __len__ ( )
PySide.QtCore.QByteArray. __reduce__ ( )
返回类型: PyObject
PySide.QtCore.QByteArray. __repr__ ( )
返回类型: PyObject
PySide.QtCore.QByteArray. __setitem__ ( )
PySide.QtCore.QByteArray. __str__ ( )
返回类型: PyObject
PySide.QtCore.QByteArray. append ( c )
参数: c PySide.QtCore.char
返回类型: PySide.QtCore.QByteArray

这是重载函数。

追加字符 ch 到此字节数组。

PySide.QtCore.QByteArray. append ( a )
参数: a PySide.QtCore.QByteArray
返回类型: PySide.QtCore.QByteArray

Appends the byte array ba onto the end of this byte array.

范例:

x = QByteArray("free")
y = QByteArray("dom")
x.append(y)
# x == "freedom"
												

This is the same as insert( PySide.QtCore.QByteArray.size() , ba ).

注意: PySide.QtCore.QByteArray 隐式共享 class. Consequently, if this is an empty PySide.QtCore.QByteArray ,那么 this will just share the data held in ba . In this case, no copying of data is done, taking constant time . If a shared instance is modified, it will be copied (copy-on-write), taking linear time .

this is not an empty PySide.QtCore.QByteArray , a deep copy of the data is performed, taking linear time .

This operation typically does not suffer from allocation overhead, because PySide.QtCore.QByteArray preallocates extra space at the end of the data so that it may grow without reallocating for each append operation.

另请参阅

PySide.QtCore.QByteArray.operator+=() PySide.QtCore.QByteArray.prepend() PySide.QtCore.QByteArray.insert()

PySide.QtCore.QByteArray. at ( i )
参数: i PySide.QtCore.int
返回类型: PySide.QtCore.char

Returns the character at index position i in the byte array.

i must be a valid index position in the byte array (i.e., 0 <= i < PySide.QtCore.QByteArray.size() ).

另请参阅

PySide.QtCore.QByteArray.operator[]()

PySide.QtCore.QByteArray. capacity ( )
返回类型: PySide.QtCore.int

Returns the maximum number of bytes that can be stored in the byte array without forcing a reallocation.

The sole purpose of this function is to provide a means of fine tuning PySide.QtCore.QByteArray ‘s memory usage. In general, you will rarely ever need to call this function. If you want to know how many bytes are in the byte array, call PySide.QtCore.QByteArray.size() .

PySide.QtCore.QByteArray. chop ( n )
参数: n PySide.QtCore.int

移除 n bytes from the end of the byte array.

n 大于 PySide.QtCore.QByteArray.size() , the result is an empty byte array.

范例:

ba = QByteArray("STARTTLS\r\n")
ba.chop(2)                 # ba == "STARTTLS"
												
PySide.QtCore.QByteArray. clear ( )

Clears the contents of the byte array and makes it empty.

PySide.QtCore.QByteArray. contains ( a )
参数: a PySide.QtCore.QByteArray
返回类型: PySide.QtCore.QBool

Returns true if the byte array contains an occurrence of the byte array ba ;否则返回 false。

PySide.QtCore.QByteArray. contains ( c )
参数: c PySide.QtCore.char
返回类型: PySide.QtCore.QBool

这是重载函数。

Returns true if the byte array contains the character ch ;否则返回 false。

PySide.QtCore.QByteArray. count ( a )
参数: a PySide.QtCore.QByteArray
返回类型: PySide.QtCore.int

Returns the number of (potentially overlapping) occurrences of byte array ba in this byte array.

PySide.QtCore.QByteArray. count ( c )
参数: c PySide.QtCore.char
返回类型: PySide.QtCore.int

这是重载函数。

Returns the number of occurrences of character ch in the byte array.

PySide.QtCore.QByteArray. count ( )
返回类型: PySide.QtCore.int

这是重载函数。

如同 PySide.QtCore.QByteArray.size() .

PySide.QtCore.QByteArray. data ( )
返回类型: str

这是重载函数。

PySide.QtCore.QByteArray. endsWith ( a )
参数: a PySide.QtCore.QByteArray
返回类型: PySide.QtCore.bool

Returns true if this byte array ends with byte array ba ;否则返回 false。

范例:

url = QByteArray("http://qtsoftware.com/index.html")
if url.endsWith(".html"):
    ...
												
PySide.QtCore.QByteArray. endsWith ( c )
参数: c PySide.QtCore.char
返回类型: PySide.QtCore.bool

这是重载函数。

Returns true if this byte array ends with character ch ;否则返回 false。

PySide.QtCore.QByteArray. expand ( i )
参数: i PySide.QtCore.int
PySide.QtCore.QByteArray. fill ( c [ , size=-1 ] )
参数:
  • c PySide.QtCore.char
  • size PySide.QtCore.int
返回类型:

PySide.QtCore.QByteArray

Sets every byte in the byte array to character ch 。若 size is different from -1 (the default), the byte array is resized to size size beforehand.

范例:

ba = QByteArray("Istambul")
ba.fill('o')
# ba == "oooooooo"
ba.fill('X', 2)
# ba == "XX"
												
static PySide.QtCore.QByteArray. fromBase64 ( base64 )
参数: base64 PySide.QtCore.QByteArray
返回类型: PySide.QtCore.QByteArray

Returns a decoded copy of the Base64 array base64 . Input is not checked for validity; invalid characters in the input are skipped, enabling the decoding process to continue with subsequent characters.

例如:

text = QByteArray.fromBase64("UXQgaXMgZ3JlYXQh")
text.data()            # returns "Qt is great!"
												

The algorithm used to decode Base64-encoded data is defined in RFC 2045 .

static PySide.QtCore.QByteArray. fromHex ( hexEncoded )
参数: hexEncoded PySide.QtCore.QByteArray
返回类型: PySide.QtCore.QByteArray

Returns a decoded copy of the hex encoded array hexEncoded . Input is not checked for validity; invalid characters in the input are skipped, enabling the decoding process to continue with subsequent characters.

例如:

text = QByteArray.fromHex("517420697320677265617421")
text.data()            # returns "Qt is great!"
												
static PySide.QtCore.QByteArray. fromPercentEncoding ( pctEncoded [ , percent='%' ] )
参数:
返回类型:

PySide.QtCore.QByteArray

Returns a decoded copy of the URI/URL-style percent-encoded input percent parameter allows you to replace the ‘%' character for another (for instance, ‘ _ ‘ or ‘=').

例如:

QByteArray text = QByteArray::fromPercentEncoding("Qt%20is%20great%33");
text.data();            // returns "Qt is great!"
											
static PySide.QtCore.QByteArray. fromRawData ( arg__1 )
参数: arg__1 – str
返回类型: PySide.QtCore.QByteArray

构造 PySide.QtCore.QByteArray that uses the first size bytes of the data array. The bytes are not copied. The PySide.QtCore.QByteArray will contain the data pointer. The caller guarantees that data will not be deleted or modified as long as this PySide.QtCore.QByteArray and any copies of it exist that have not been modified. In other words, because PySide.QtCore.QByteArray 隐式共享 class and the instance returned by this function contains the data pointer, the caller must not delete data or modify it directly as long as the returned PySide.QtCore.QByteArray and any copies exist. However, PySide.QtCore.QByteArray 未拥有所有权对于 data , so the PySide.QtCore.QByteArray destructor will never delete the raw data , even when the last PySide.QtCore.QByteArray referring to data 被销毁。

A subsequent attempt to modify the contents of the returned PySide.QtCore.QByteArray or any copy made from it will cause it to create a deep copy of the data array before doing the modification. This ensures that the raw data array itself will never be modified by PySide.QtCore.QByteArray .

Here is an example of how to read data using a PySide.QtCore.QDataStream on raw data in memory without copying the raw data into a PySide.QtCore.QByteArray :

mydata = '\x00\x00\x03\x84\x78\x9c\x3b\x76'\
         '\xec\x18\xc3\x31\x0a\xf1\xcc\x99'\
         ...
         '\x6d\x5b'
data = QByteArray.fromRawData(mydata)
in_ = QDataStream(data, QIODevice.ReadOnly)
...
											

警告

A byte array created with PySide.QtCore.QByteArray.fromRawData() is not null-terminated, unless the raw data contains a 0 character at position size . While that does not matter for PySide.QtCore.QDataStream or functions like PySide.QtCore.QByteArray.indexOf() , passing the byte array to a function accepting a const char * expected to be ‘0'-terminated will fail.

另请参阅

PySide.QtCore.QByteArray.setRawData() PySide.QtCore.QByteArray.data() PySide.QtCore.QByteArray.constData()

PySide.QtCore.QByteArray. indexOf ( a [ , from=0 ] )
参数:
返回类型:

PySide.QtCore.int

Returns the index position of the first occurrence of the byte array ba in this byte array, searching forward from index position from . Returns -1 if ba could not be found.

范例:

x = QByteArray("sticky question")
y = QByteArray("sti")
x.indexOf(y)               # returns 0
x.indexOf(y, 1)            # returns 10
x.indexOf(y, 10)           # returns 10
x.indexOf(y, 11)           # returns -1
												
PySide.QtCore.QByteArray. insert ( i , a )
参数:
返回类型:

PySide.QtCore.QByteArray

Inserts the byte array ba at index position i and returns a reference to this byte array.

范例:

ba = QByteArray("Meal")
ba.insert(1, QByteArray("ontr"))
# ba == "Montreal"
												
PySide.QtCore.QByteArray. isEmpty ( )
返回类型: PySide.QtCore.bool

Returns true if the byte array has size 0; otherwise returns false.

范例:

QByteArray().isEmpty()         # returns true
QByteArray("").isEmpty()       # returns true
QByteArray("abc").isEmpty()    # returns false
												
PySide.QtCore.QByteArray. isNull ( )
返回类型: PySide.QtCore.bool

Returns true if this byte array is null; otherwise returns false.

范例:

QByteArray().isNull()          # returns true
QByteArray("").isNull()        # returns false
QByteArray("abc").isNull()     # returns false
												

Qt makes a distinction between null byte arrays and empty byte arrays for historical reasons. For most applications, what matters is whether or not a byte array contains any data, and this can be determined using PySide.QtCore.QByteArray.isEmpty() .

PySide.QtCore.QByteArray. isSharedWith ( other )
参数: other PySide.QtCore.QByteArray
返回类型: PySide.QtCore.bool
PySide.QtCore.QByteArray. lastIndexOf ( a [ , from=-1 ] )
参数:
返回类型:

PySide.QtCore.int

Returns the index position of the last occurrence of the byte array ba in this byte array, searching backward from index position from 。若 from is -1 (the default), the search starts at the last byte. Returns -1 if ba could not be found.

范例:

x = QByteArray("crazy azimuths")
y = QByteArray("azy")
x.lastIndexOf(y)           # returns 6
x.lastIndexOf(y, 6)        # returns 6
x.lastIndexOf(y, 5)        # returns 2
x.lastIndexOf(y, 1)        # returns -1
												
PySide.QtCore.QByteArray. left ( len )
参数: len PySide.QtCore.int
返回类型: PySide.QtCore.QByteArray

返回的字节数组包含最左 len 字节在此字节数组。

返回整个字节数组若 len 大于 PySide.QtCore.QByteArray.size() .

范例:

x = QByteArray("Pineapple")
y = x.left(4)
# y == "Pine"
												
PySide.QtCore.QByteArray. leftJustified ( width [ , fill=' ' [ , truncate=false ] ] )
参数:
  • width PySide.QtCore.int
  • fill PySide.QtCore.char
  • truncate PySide.QtCore.bool
返回类型:

PySide.QtCore.QByteArray

Returns a byte array of size width that contains this byte array padded by the fill character.

truncate is false and the PySide.QtCore.QByteArray.size() of the byte array is more than width , then the returned byte array is a copy of this byte array.

truncate is true and the PySide.QtCore.QByteArray.size() of the byte array is more than width , then any bytes in a copy of the byte array after position width are removed, and the copy is returned.

范例:

x = QByteArray("apple")
y = x.leftJustified(8, '.')   # y == "apple..."
												
PySide.QtCore.QByteArray. length ( )
返回类型: PySide.QtCore.int

如同 PySide.QtCore.QByteArray.size() .

PySide.QtCore.QByteArray. mid ( index [ , len=-1 ] )
参数:
  • index PySide.QtCore.int
  • len PySide.QtCore.int
返回类型:

PySide.QtCore.QByteArray

Returns a byte array containing len bytes from this byte array, starting at position pos .

len is -1 (the default), or pos + len >= PySide.QtCore.QByteArray.size() , returns a byte array containing all bytes starting at position pos until the end of the byte array.

范例:

x = QByteArray("Five pineapples")
y = x.mid(5, 4)     # y == "pine"
z = x.mid(5)        # z == "pineapples"
												
PySide.QtCore.QByteArray. nulTerminated ( )
返回类型: PySide.QtCore.QByteArray
static PySide.QtCore.QByteArray. number ( arg__1 [ , base=10 ] )
参数:
  • arg__1 PySide.QtCore.int
  • base PySide.QtCore.int
返回类型:

PySide.QtCore.QByteArray

Returns a byte array containing the string equivalent of the number n to base base (10 by default). The base can be any value between 2 and 36.

范例:

n = 63;
QByteArray.number(n)               # returns "63"
QByteArray.number(n, 16)           # returns "3f"
QByteArray.number(n, 16).toUpper() # returns "3F"
												

注意

The format of the number is not localized; the default C locale is used irrespective of the user's locale.

static PySide.QtCore.QByteArray. number ( arg__1 [ , base=10 ] )
参数:
  • arg__1 PySide.QtCore.qlonglong
  • base PySide.QtCore.int
返回类型:

PySide.QtCore.QByteArray

这是重载函数。

static PySide.QtCore.QByteArray. number ( arg__1 [ , f='g' [ , prec=6 ] ] )
参数:
  • arg__1 PySide.QtCore.double
  • f PySide.QtCore.char
  • prec PySide.QtCore.int
返回类型:

PySide.QtCore.QByteArray

这是重载函数。

Returns a byte array that contains the printed value of n , formatted in format f with precision prec .

Argument n is formatted according to the f format specified, which is g by default, and can be any of the following:

格式 含义
e format as [-]9.9e[+|-]999
E format as [-]9.9E[+|-]999
f format as [-]9.9
g use e or f format, whichever is the most concise
G use E or f format, whichever is the most concise

With ‘e', ‘E', and ‘f', prec is the number of digits after the decimal point. With ‘g' and ‘G', prec is the maximum number of significant digits (trailing zeroes are omitted).

ba = QByteArray.number(12.3456, 'E', 3)
# ba == 1.235E+01
												

注意

The format of the number is not localized; the default C locale is used irrespective of the user's locale.

PySide.QtCore.QByteArray. __ne__ ( a2 )
参数: a2 PySide.QtCore.QByteArray
返回类型: PySide.QtCore.bool
PySide.QtCore.QByteArray. __add__ ( a2 )
参数: a2 PySide.QtCore.QByteArray
返回类型: PySide.QtCore.QByteArray
PySide.QtCore.QByteArray. __add__ ( arg__1 )
参数: arg__1 PyUnicode
PySide.QtCore.QByteArray. __add__ ( arg__1 )
参数: arg__1 PyBytes
PySide.QtCore.QByteArray. __add__ ( a2 )
参数: a2 PySide.QtCore.char
返回类型: PySide.QtCore.QByteArray
PySide.QtCore.QByteArray. __add__ ( arg__1 )
参数: arg__1 PyUnicode
PySide.QtCore.QByteArray. __add__ ( a1 )
参数: a1 PySide.QtCore.char
返回类型: PySide.QtCore.QByteArray
PySide.QtCore.QByteArray. __iadd__ ( a )
参数: a PySide.QtCore.QByteArray
返回类型: PySide.QtCore.QByteArray

Appends the byte array ba onto the end of this byte array and returns a reference to this byte array.

范例:

x = QByteArray("free")
y = QByteArray("dom");
x += y
# x == "freedom"
												

注意: PySide.QtCore.QByteArray 隐式共享 class. Consequently, if this is an empty PySide.QtCore.QByteArray ,那么 this will just share the data held in ba . In this case, no copying of data is done, taking constant time . If a shared instance is modified, it will be copied (copy-on-write), taking linear time .

this is not an empty PySide.QtCore.QByteArray , a deep copy of the data is performed, taking linear time .

This operation typically does not suffer from allocation overhead, because PySide.QtCore.QByteArray preallocates extra space at the end of the data so that it may grow without reallocating for each append operation.

PySide.QtCore.QByteArray. __iadd__ ( c )
参数: c PySide.QtCore.char
返回类型: PySide.QtCore.QByteArray

这是重载函数。

追加字符 ch onto the end of this byte array and returns a reference to this byte array.

PySide.QtCore.QByteArray. __lt__ ( a2 )
参数: a2 – str
返回类型: PySide.QtCore.bool
PySide.QtCore.QByteArray. __lt__ ( a2 )
参数: a2 PySide.QtCore.QByteArray
返回类型: PySide.QtCore.bool
PySide.QtCore.QByteArray. __le__ ( a2 )
参数: a2 PySide.QtCore.QByteArray
返回类型: PySide.QtCore.bool
PySide.QtCore.QByteArray. __eq__ ( a2 )
参数: a2 PySide.QtCore.QByteArray
返回类型: PySide.QtCore.bool
PySide.QtCore.QByteArray. __gt__ ( a2 )
参数: a2 PySide.QtCore.QByteArray
返回类型: PySide.QtCore.bool
PySide.QtCore.QByteArray. __ge__ ( a2 )
参数: a2 PySide.QtCore.QByteArray
返回类型: PySide.QtCore.bool
PySide.QtCore.QByteArray. prepend ( a )
参数: a PySide.QtCore.QByteArray
返回类型: PySide.QtCore.QByteArray

前置字节数组 ba 到此字节数组,并返回此字节数组的引用。

范例:

x = QByteArray("ship")
y = QByteArray("air")
x.prepend(y)
# x == "airship"
												

这如同 insert(0, ba ).

注意: PySide.QtCore.QByteArray 隐式共享 class. Consequently, if this is an empty PySide.QtCore.QByteArray ,那么 this will just share the data held in ba . In this case, no copying of data is done, taking constant time . If a shared instance is modified, it will be copied (copy-on-write), taking linear time .

this is not an empty PySide.QtCore.QByteArray , a deep copy of the data is performed, taking linear time .

PySide.QtCore.QByteArray. prepend ( c )
参数: c PySide.QtCore.char
返回类型: PySide.QtCore.QByteArray

这是重载函数。

前置字符 ch 到此字节数组。

PySide.QtCore.QByteArray. realloc ( alloc )
参数: alloc PySide.QtCore.int
PySide.QtCore.QByteArray. remove ( index , len )
参数:
  • index PySide.QtCore.int
  • len PySide.QtCore.int
返回类型:

PySide.QtCore.QByteArray

移除 len bytes from the array, starting at index position pos , and returns a reference to the array.

pos is out of range, nothing happens. If pos is valid, but pos + len is larger than the size of the array, the array is truncated at position pos .

范例:

ba = QByteArray("Montreal")
ba.remove(1, 4)
# ba == "Meal"
												
PySide.QtCore.QByteArray. repeated ( times )
参数: times PySide.QtCore.int
返回类型: PySide.QtCore.QByteArray

Returns a copy of this byte array repeated the specified number of times .

times is less than 1, an empty byte array is returned.

范例:

QByteArray ba("ab");
ba.repeated(4);             // returns "abababab"
											
PySide.QtCore.QByteArray. replace ( index , len , s )
参数:
返回类型:

PySide.QtCore.QByteArray

替换 len bytes from index position pos with the byte array after , and returns a reference to this byte array.

范例:

x = QByteArray("Say yes!")
y = QByteArray("no")
x.replace(4, 3, y)
# x == "Say no!"
												
PySide.QtCore.QByteArray. replace ( before , after )
参数:
返回类型:

PySide.QtCore.QByteArray

这是重载函数。

Replaces every occurrence of the string before with the byte array after . The Unicode data is converted into 8-bit characters using QString.toAscii() .

PySide.QtCore.QString contains non-ASCII Unicode characters, using this function can lead to loss of information. You can disable this function by defining QT_NO_CAST_TO_ASCII when you compile your applications. You then need to call QString.toAscii() (或 QString.toLatin1() or QString.toUtf8() or QString.toLocal8Bit() ) explicitly if you want to convert the data to const char * .

PySide.QtCore.QByteArray. replace ( before , after )
参数:
  • before PySide.QtCore.char
  • after PySide.QtCore.char
返回类型:

PySide.QtCore.QByteArray

这是重载函数。

Replaces every occurrence of the character before with the character after .

PySide.QtCore.QByteArray. replace ( before , after )
参数:
返回类型:

PySide.QtCore.QByteArray

这是重载函数。

Replaces every occurrence of the character before with the byte array after .

PySide.QtCore.QByteArray. replace ( before , after )
参数:
返回类型:

PySide.QtCore.QByteArray

这是重载函数。

Replaces every occurrence of the byte array before with the byte array after .

范例:

ba = QByteArray("colour behaviour flavour neighbour")
ba.replace(QByteArray("ou"), QByteArray("o"))
# ba == "color behavior flavor neighbor"
												
PySide.QtCore.QByteArray. reserve ( size )
参数: size PySide.QtCore.int

Attempts to allocate memory for at least size bytes. If you know in advance how large the byte array will be, you can call this function, and if you call PySide.QtCore.QByteArray.resize() often you are likely to get better performance. If size is an underestimate, the worst that will happen is that the PySide.QtCore.QByteArray will be a bit slower.

The sole purpose of this function is to provide a means of fine tuning PySide.QtCore.QByteArray ‘s memory usage. In general, you will rarely ever need to call this function. If you want to change the size of the byte array, call PySide.QtCore.QByteArray.resize() .

PySide.QtCore.QByteArray. resize ( size )
参数: size PySide.QtCore.int

把字节数组的尺寸设为 size 字节。

size is greater than the current size, the byte array is extended to make it size bytes with the extra bytes added to the end. The new bytes are uninitialized.

size is less than the current size, bytes are removed from the end.

PySide.QtCore.QByteArray. right ( len )
参数: len PySide.QtCore.int
返回类型: PySide.QtCore.QByteArray

返回的字节数组包含最右 len 字节在此字节数组。

返回整个字节数组若 len 大于 PySide.QtCore.QByteArray.size() .

范例:

x = QByteArray("Pineapple")
y = x.right(5)
# y == "apple"
												
PySide.QtCore.QByteArray. rightJustified ( width [ , fill=' ' [ , truncate=false ] ] )
参数:
  • width PySide.QtCore.int
  • fill PySide.QtCore.char
  • truncate PySide.QtCore.bool
返回类型:

PySide.QtCore.QByteArray

Returns a byte array of size width that contains the fill character followed by this byte array.

truncate is false and the size of the byte array is more than width , then the returned byte array is a copy of this byte array.

truncate is true and the size of the byte array is more than width , then the resulting byte array is truncated at position width .

范例:

x = QByteArray("apple")
y = x.rightJustified(8, '.')    # y == "...apple"
												
PySide.QtCore.QByteArray. setNum ( arg__1 [ , f='g' [ , prec=6 ] ] )
参数:
  • arg__1 PySide.QtCore.double
  • f PySide.QtCore.char
  • prec PySide.QtCore.int
返回类型:

PySide.QtCore.QByteArray

这是重载函数。

Sets the byte array to the printed value of n , formatted in format f with precision prec , and returns a reference to the byte array.

格式 f 可以是下列任一:

格式 含义
e format as [-]9.9e[+|-]999
E format as [-]9.9E[+|-]999
f format as [-]9.9
g use e or f format, whichever is the most concise
G use E or f format, whichever is the most concise

With ‘e', ‘E', and ‘f', prec is the number of digits after the decimal point. With ‘g' and ‘G', prec is the maximum number of significant digits (trailing zeroes are omitted).

注意

The format of the number is not localized; the default C locale is used irrespective of the user's locale.

PySide.QtCore.QByteArray. setNum ( arg__1 [ , base=10 ] )
参数:
  • arg__1 PySide.QtCore.qlonglong
  • base PySide.QtCore.int
返回类型:

PySide.QtCore.QByteArray

这是重载函数。

PySide.QtCore.QByteArray. setNum ( arg__1 [ , base=10 ] )
参数:
  • arg__1 PySide.QtCore.int
  • base PySide.QtCore.int
返回类型:

PySide.QtCore.QByteArray

Sets the byte array to the printed value of n in base base (10 by default) and returns a reference to the byte array. The base can be any value between 2 and 36.

范例:

ba = QByteArray()
n = 63
ba.setNum(n)           # ba == "63"
ba.setNum(n, 16)       # ba == "3f"
												

注意

The format of the number is not localized; the default C locale is used irrespective of the user's locale.

PySide.QtCore.QByteArray. setRawData ( a , n )
参数:
  • a – str
  • n PySide.QtCore.uint
返回类型:

PySide.QtCore.QByteArray

Resets the PySide.QtCore.QByteArray to use the first size bytes of the data array. The bytes are not copied. The PySide.QtCore.QByteArray will contain the data pointer. The caller guarantees that data will not be deleted or modified as long as this PySide.QtCore.QByteArray and any copies of it exist that have not been modified.

This function can be used instead of PySide.QtCore.QByteArray.fromRawData() to re-use existings PySide.QtCore.QByteArray objects to save memory re-allocations.

另请参阅

PySide.QtCore.QByteArray.fromRawData() PySide.QtCore.QByteArray.data() PySide.QtCore.QByteArray.constData()

PySide.QtCore.QByteArray. simplified ( )
返回类型: PySide.QtCore.QByteArray

Returns a byte array that has whitespace removed from the start and the end, and which has each sequence of internal whitespace replaced with a single space.

Whitespace means any character for which the standard C++ isspace() function returns true. This includes the ASCII characters ‘t', ‘n', ‘v', ‘f', ‘r', and ‘ ‘.

范例:

ba = QByteArray("  lots\t of\nwhitespace\r\n ")
ba = ba.simplified()
# ba == "lots of whitespace";
												
PySide.QtCore.QByteArray. size ( )
返回类型: PySide.QtCore.int

返回此字节数组的字节数。

The last byte in the byte array is at position PySide.QtCore.QByteArray.size() - 1. In addition, PySide.QtCore.QByteArray ensures that the byte at position PySide.QtCore.QByteArray.size() is always ‘0', so that you can use the return value of PySide.QtCore.QByteArray.data() and PySide.QtCore.QByteArray.constData() as arguments to functions that expect ‘0'-terminated strings. If the PySide.QtCore.QByteArray object was created from a raw data that didn't include the trailing null-termination character then PySide.QtCore.QByteArray doesn't add it automaticall unless the deep copy is created.

范例:

ba = QByteArray("Hello")
n = ba.size()          # n == 5
ba.data()[0]           # returns 'H'
ba.data()[4]           # returns 'o'
												
PySide.QtCore.QByteArray. split ( sep )
参数: sep PySide.QtCore.char
返回类型:

Splits the byte array into subarrays wherever sep occurs, and returns the list of those arrays. If sep does not match anywhere in the byte array, PySide.QtCore.QByteArray.split() returns a single-element list containing this byte array.

PySide.QtCore.QByteArray. squeeze ( )

Releases any memory not required to store the array's data.

The sole purpose of this function is to provide a means of fine tuning PySide.QtCore.QByteArray ‘s memory usage. In general, you will rarely ever need to call this function.

PySide.QtCore.QByteArray. startsWith ( a )
参数: a PySide.QtCore.QByteArray
返回类型: PySide.QtCore.bool

Returns true if this byte array starts with byte array ba ;否则返回 false。

范例:

url = QByteArray("ftp://ftp.trolltech.com/")
if url.startsWith("ftp:"):
    ...
												
PySide.QtCore.QByteArray. startsWith ( c )
参数: c PySide.QtCore.char
返回类型: PySide.QtCore.bool

这是重载函数。

Returns true if this byte array starts with character ch ;否则返回 false。

PySide.QtCore.QByteArray. swap ( other )
参数: other PySide.QtCore.QByteArray

Swaps byte array other with this byte array. This operation is very fast and never fails.

PySide.QtCore.QByteArray. toBase64 ( )
返回类型: PySide.QtCore.QByteArray

Returns a copy of the byte array, encoded as Base64.

text = QByteArray("Qt is great!")
text.toBase64()        # returns "UXQgaXMgZ3JlYXQh"
												

The algorithm used to encode Base64-encoded data is defined in RFC 2045 .

PySide.QtCore.QByteArray. toDouble ( )
返回类型: PySide.QtCore.double

Returns the byte array converted to a double 值。

Returns 0.0 if the conversion fails.

ok is not 0: if a conversion error occurs, *``ok`` is set to false; otherwise *``ok`` is set to true.

string = QByteArray("1234.56")
(a, ok) = string.toDouble()   # a == 1234.56, ok == true
												

注意

The conversion of the number is performed in the default C locale, irrespective of the user's locale.

PySide.QtCore.QByteArray. toFloat ( )
返回类型: PySide.QtCore.float

Returns the byte array converted to a float 值。

Returns 0.0 if the conversion fails.

ok is not 0: if a conversion error occurs, *``ok`` is set to false; otherwise *``ok`` is set to true.

注意

The conversion of the number is performed in the default C locale, irrespective of the user's locale.

PySide.QtCore.QByteArray. toHex ( )
返回类型: PySide.QtCore.QByteArray

Returns a hex encoded copy of the byte array. The hex encoding uses the numbers 0-9 and the letters a-f.

PySide.QtCore.QByteArray. toInt ( [ base=10 ] )
参数: base PySide.QtCore.int
返回类型: PySide.QtCore.int

Returns the byte array converted to an int using base base , which is 10 by default and must be between 2 and 36, or 0.

base is 0, the base is determined automatically using the following rules: If the byte array begins with “0x”, it is assumed to be hexadecimal; if it begins with “0”, it is assumed to be octal; otherwise it is assumed to be decimal.

返回 0,若转换失败。

ok is not 0: if a conversion error occurs, *``ok`` is set to false; otherwise *``ok`` is set to true.

string = QByteArray("FF")
(hex, ok) = string.toInt(16)   # hex == 255, ok == true
(dec, ok) = string.toInt(10)   # dec == 0, ok == false
												

注意

The conversion of the number is performed in the default C locale, irrespective of the user's locale.

PySide.QtCore.QByteArray. toLong ( [ base=10 ] )
参数: base PySide.QtCore.int
返回类型: PySide.QtCore.long

Returns the byte array converted to a long int using base base , which is 10 by default and must be between 2 and 36, or 0.

base is 0, the base is determined automatically using the following rules: If the byte array begins with “0x”, it is assumed to be hexadecimal; if it begins with “0”, it is assumed to be octal; otherwise it is assumed to be decimal.

返回 0,若转换失败。

ok is not 0: if a conversion error occurs, *``ok`` is set to false; otherwise *``ok`` is set to true.

string = QByteArray("FF")
(hex, ok) = str.toLong(16);    # hex == 255, ok == true
(dec, ok) = str.toLong(10);    # dec == 0, ok == false
												

注意

The conversion of the number is performed in the default C locale, irrespective of the user's locale.

PySide.QtCore.QByteArray. toLongLong ( [ base=10 ] )
参数: base PySide.QtCore.int
返回类型: PySide.QtCore.qlonglong

Returns the byte array converted to a long long using base base , which is 10 by default and must be between 2 and 36, or 0.

base is 0, the base is determined automatically using the following rules: If the byte array begins with “0x”, it is assumed to be hexadecimal; if it begins with “0”, it is assumed to be octal; otherwise it is assumed to be decimal.

返回 0,若转换失败。

ok is not 0: if a conversion error occurs, *``ok`` is set to false; otherwise *``ok`` is set to true.

注意

The conversion of the number is performed in the default C locale, irrespective of the user's locale.

PySide.QtCore.QByteArray. toLower ( )
返回类型: PySide.QtCore.QByteArray

Returns a lowercase copy of the byte array. The bytearray is interpreted as a Latin-1 encoded string.

范例:

x = QByteArray("TROlltECH")
y = x.toLower()
# y == "trolltech"
												

另请参阅

PySide.QtCore.QByteArray.toUpper() 8 位 字符 比较

PySide.QtCore.QByteArray. toPercentEncoding ( [ exclude=QByteArray() [ , include=QByteArray() [ , percent='%' ] ] ] )
参数:
返回类型:

PySide.QtCore.QByteArray

Returns a URI/URL-style percent-encoded copy of this byte array. The percent parameter allows you to override the default ‘%' character for another.

By default, this function will encode all characters that are not one of the following:

ALPHA (“a” to “z” and “A” to “Z”) / DIGIT (0 to 9) / “-” / ”.” / ” _ ” / “~”

To prevent characters from being encoded pass them to exclude . To force characters to be encoded pass them to include percent character is always encoded.

范例:

QByteArray text = "{a fishy string?}";
QByteArray ba = text.toPercentEncoding("{}", "s");
qDebug(ba.constData());
// prints "{a fi%73hy %73tring%3F}"
											

The hex encoding uses the numbers 0-9 and the uppercase letters A-F.

PySide.QtCore.QByteArray. toShort ( [ base=10 ] )
参数: base PySide.QtCore.int
返回类型: PySide.QtCore.short

Returns the byte array converted to a short using base base , which is 10 by default and must be between 2 and 36, or 0.

base is 0, the base is determined automatically using the following rules: If the byte array begins with “0x”, it is assumed to be hexadecimal; if it begins with “0”, it is assumed to be octal; otherwise it is assumed to be decimal.

返回 0,若转换失败。

ok is not 0: if a conversion error occurs, *``ok`` is set to false; otherwise *``ok`` is set to true.

注意

The conversion of the number is performed in the default C locale, irrespective of the user's locale.

PySide.QtCore.QByteArray. toUInt ( [ base=10 ] )
参数: base PySide.QtCore.int
返回类型: PySide.QtCore.uint

Returns the byte array converted to an unsigned int using base base , which is 10 by default and must be between 2 and 36, or 0.

base is 0, the base is determined automatically using the following rules: If the byte array begins with “0x”, it is assumed to be hexadecimal; if it begins with “0”, it is assumed to be octal; otherwise it is assumed to be decimal.

返回 0,若转换失败。

ok is not 0: if a conversion error occurs, *``ok`` is set to false; otherwise *``ok`` is set to true.

注意

The conversion of the number is performed in the default C locale, irrespective of the user's locale.

PySide.QtCore.QByteArray. toULong ( [ base=10 ] )
参数: base PySide.QtCore.int
返回类型: PySide.QtCore.ulong

Returns the byte array converted to an unsigned long int using base base , which is 10 by default and must be between 2 and 36, or 0.

base is 0, the base is determined automatically using the following rules: If the byte array begins with “0x”, it is assumed to be hexadecimal; if it begins with “0”, it is assumed to be octal; otherwise it is assumed to be decimal.

返回 0,若转换失败。

ok is not 0: if a conversion error occurs, *``ok`` is set to false; otherwise *``ok`` is set to true.

注意

The conversion of the number is performed in the default C locale, irrespective of the user's locale.

PySide.QtCore.QByteArray. toULongLong ( [ base=10 ] )
参数: base PySide.QtCore.int
返回类型: PySide.QtCore.qulonglong

Returns the byte array converted to an unsigned long long using base base , which is 10 by default and must be between 2 and 36, or 0.

base is 0, the base is determined automatically using the following rules: If the byte array begins with “0x”, it is assumed to be hexadecimal; if it begins with “0”, it is assumed to be octal; otherwise it is assumed to be decimal.

返回 0,若转换失败。

ok is not 0: if a conversion error occurs, *``ok`` is set to false; otherwise *``ok`` is set to true.

注意

The conversion of the number is performed in the default C locale, irrespective of the user's locale.

PySide.QtCore.QByteArray. toUShort ( [ base=10 ] )
参数: base PySide.QtCore.int
返回类型: PySide.QtCore.ushort

Returns the byte array converted to an unsigned short using base base , which is 10 by default and must be between 2 and 36, or 0.

base is 0, the base is determined automatically using the following rules: If the byte array begins with “0x”, it is assumed to be hexadecimal; if it begins with “0”, it is assumed to be octal; otherwise it is assumed to be decimal.

返回 0,若转换失败。

ok is not 0: if a conversion error occurs, *``ok`` is set to false; otherwise *``ok`` is set to true.

注意

The conversion of the number is performed in the default C locale, irrespective of the user's locale.

PySide.QtCore.QByteArray. toUpper ( )
返回类型: PySide.QtCore.QByteArray

Returns an uppercase copy of the byte array. The bytearray is interpreted as a Latin-1 encoded string.

范例:

x = QByteArray("TROlltECH")
y = x.toUpper()
# y == "TROLLTECH"
												

另请参阅

PySide.QtCore.QByteArray.toLower() 8 位 字符 比较

PySide.QtCore.QByteArray. trimmed ( )
返回类型: PySide.QtCore.QByteArray

Returns a byte array that has whitespace removed from the start and the end.

Whitespace means any character for which the standard C++ isspace() function returns true. This includes the ASCII characters ‘t', ‘n', ‘v', ‘f', ‘r', and ‘ ‘.

范例:

ba = QByteArray("  lots\t of\nwhitespace\r\n ");
ba = ba.trimmed();
# ba == "lots\t of\nwhitespace";
												

不像 PySide.QtCore.QByteArray.simplified() , PySide.QtCore.QByteArray.trimmed() leaves internal whitespace alone.

PySide.QtCore.QByteArray. truncate ( pos )
参数: pos PySide.QtCore.int

Truncates the byte array at index position pos .

pos is beyond the end of the array, nothing happens.

范例:

ba = QByteArray("Stockholm")
ba.truncate(5)             # ba == "Stock"