QBitArray¶

The QBitArray class provides an array of bits. More…

Synopsis¶

Functions¶

def __and__ (, arg__2)
def __and__ (, arg__2)
def __eq__ (other)
def __getitem__ ()
def __iand__ (arg__1)
def __ior__ (arg__1)
def __ixor__ (arg__1)
def __len__ ()
def __ne__ (other)
def __or__ (, arg__2)
def __setitem__ ()
def __xor__ (, arg__2)
def at (i)
def bits ()
def clear ()
def clearBit (i)
def count ()
def count (on)
def fill (val, first, last)
def fill (val[, size=-1])
def isEmpty ()
def isNull ()
def operator[] (i)
def operator[] (i)
def operator~ ()
def resize (size)
def setBit (i)
def setBit (i, val)
def size ()
def swap (other)
def testBit (i)
def toggleBit (i)
def truncate (pos)

Static functions¶

def fromBits (data, len)

Detailed Description¶

A QBitArray is an array that gives access to individual bits and provides operators ( AND , OR , XOR , and NOT ) that work on entire arrays of bits. It uses implicit sharing (copy-on-write) to reduce memory usage and to avoid the needless copying of data.

The following code constructs a QBitArray containing 200 bits initialized to false (0):
ba = QBitArray(200)
To initialize the bits to true, either pass true as second argument to the constructor, or call fill() later on.

QBitArray uses 0-based indexes, just like C++ arrays. To access the bit at a particular index position, you can use operator[](). On non-const bit arrays, operator[]() returns a reference to a bit that can be used on the left side of an assignment. For example:
ba = QBitArray()
ba.resize(3)
ba[0] = True
ba[1] = False
ba[2] = True
For technical reasons, it is more efficient to use testBit() and setBit() to access bits in the array than operator[](). For example:
ba = QBitArray(3)
ba.setBit(0, True)
ba.setBit(1, False)
ba.setBit(2, True)
QBitArray supports & ( AND ), | ( OR ), ^ ( XOR ), ~ ( NOT ), as well as &= , |= , and ^= . These operators work in the same way as the built-in C++ bitwise operators of the same name. For example:
x = QBitArray(5)
x.setBit(3, True)
# x: [ 0, 0, 0, 1, 0 ]

y = QBitArray(5)
y.setBit(4, True)
# y: [ 0, 0, 0, 0, 1 ]

x |= y
# x: [ 0, 0, 0, 1, 1 ]
For historical reasons, QBitArray distinguishes between a null bit array and an empty bit array. A null bit array is a bit array that is initialized using QBitArray ‘s default constructor. An empty bit array is any bit array with size 0. A null bit array is always empty, but an empty bit array isn’t necessarily null:
QBitArray().isNull()           # returns True
QBitArray().isEmpty()          # returns True

QBitArray(0).isNull()          # returns False
QBitArray(0).isEmpty()         # returns True

QBitArray(3).isNull()          # returns False
QBitArray(3).isEmpty()         # returns False
All functions except isNull() treat null bit arrays the same as empty bit arrays; for example, QBitArray() compares equal to QBitArray (0). We recommend that you always use isEmpty() and avoid isNull() .

See also

QByteArray QVector

class PySide2.QtCore.QBitArray¶

PySide2.QtCore.QBitArray(other)

PySide2.QtCore.QBitArray(size[, val=false])

param size:

int

param other:

PySide2.QtCore.QBitArray

param val:

bool

Constructs an empty bit array.

See also

isEmpty()

Constructs a bit array containing size bits. The bits are initialized with value , which defaults to false (0).

PySide2.QtCore.QBitArray.__getitem__()¶

PySide2.QtCore.QBitArray.__len__()¶

PySide2.QtCore.QBitArray.__setitem__()¶

PySide2.QtCore.QBitArray.at(i)¶

Parameters:: i – int
Return type:: bool

Returns the value of the bit at index position i .

i must be a valid index position in the bit array (i.e., 0 <= i < size() ).

See also

operator[]()

PySide2.QtCore.QBitArray.bits()¶

Return type:: str

Returns a pointer to a dense bit array for this QBitArray . Bits are counted upwards from the least significant bit in each byte. The number of bits relevant in the last byte is given by size() % 8 .

See also

fromBits() size()

PySide2.QtCore.QBitArray.clear()¶: Clears the contents of the bit array and makes it empty.

See also

resize() isEmpty()

PySide2.QtCore.QBitArray.clearBit(i)¶

Parameters:: i – int

Sets the bit at index position i to 0.

i must be a valid index position in the bit array (i.e., 0 <= i < size() ).

See also

setBit() toggleBit()

PySide2.QtCore.QBitArray.count()¶

Return type:: int

Same as size() .

PySide2.QtCore.QBitArray.count(on)

Parameters:: on – bool
Return type:: int

If on is true, this function returns the number of 1-bits stored in the bit array; otherwise the number of 0-bits is returned.

PySide2.QtCore.QBitArray.fill(val, first, last)¶

Parameters:

val – bool
first – int
last – int

This is an overloaded function.

Sets bits at index positions begin up to (but not including) end to value .

begin must be a valid index position in the bit array (0 <= begin < size() ).

end must be either a valid index position or equal to size() , in which case the fill operation runs until the end of the array (0 <= end <= size() ).

Example:

QBitArray ba(4);
ba.fill(true, 1, 2);            // ba: [ 0, 1, 0, 0 ]
ba.fill(true, 1, 3);            // ba: [ 0, 1, 1, 0 ]
ba.fill(true, 1, 4);            // ba: [ 0, 1, 1, 1 ]

PySide2.QtCore.QBitArray.fill(val[, size=-1])

Parameters:

val – bool
size – int

Return type:

bool

Sets every bit in the bit array to value , returning true if successful; otherwise returns false . If size is different from -1 (the default), the bit array is resized to size beforehand.

Example:

ba = QBitArray(8)
ba.fill(True)
# ba: [ 1, 1, 1, 1, 1, 1, 1, 1 ]

ba.fill(False, 2)
# ba: [ 0, 0 ]

See also

resize()

static PySide2.QtCore.QBitArray.fromBits(data, len)¶

Parameters:

data – str
len – long long

Return type:

PySide2.QtCore.QBitArray

Creates a QBitArray with the dense bit array located at data , with size bits. The byte array at data must be at least size / 8 (rounded up) bytes long.

If size is not a multiple of 8, this function will include the lowest size % 8 bits from the last byte in data .

See also

bits()

PySide2.QtCore.QBitArray.isEmpty()¶

Return type:: bool

Returns true if this bit array has size 0; otherwise returns false.

See also

size()

PySide2.QtCore.QBitArray.isNull()¶

Return type:: bool

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

Example:

QBitArray().isNull()           # returns True
QBitArray(0).isNull()          # returns False
QBitArray(3).isNull()          # returns False

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

See also

isEmpty()

PySide2.QtCore.QBitArray.__ne__(other)¶

Parameters:: other – PySide2.QtCore.QBitArray
Return type:: bool

Returns true if other is not equal to this bit array; otherwise returns false .

See also

operator==()

PySide2.QtCore.QBitArray.__and__(arg__2)¶

Parameters:: arg__2 – PySide2.QtCore.QBitArray
Return type:: PySide2.QtCore.QBitArray

PySide2.QtCore.QBitArray.__and__(arg__2)

Parameters:: arg__2 – PySide2.QtCore.QBitArray
Return type:: PySide2.QtCore.QBitArray

PySide2.QtCore.QBitArray.__iand__(arg__1)¶

Parameters:: arg__1 – PySide2.QtCore.QBitArray
Return type:: PySide2.QtCore.QBitArray

PySide2.QtCore.QBitArray.__eq__(other)¶

Parameters:: other – PySide2.QtCore.QBitArray
Return type:: bool

Returns true if other is equal to this bit array; otherwise returns false .

See also

operator!=()

PySide2.QtCore.QBitArray.operator[](i)

Parameters:: i – int
Return type:: bool

This is an overloaded function.

PySide2.QtCore.QBitArray.operator[](i)

Parameters:: i – uint
Return type:: bool

This is an overloaded function.

PySide2.QtCore.QBitArray.__xor__(arg__2)¶

Parameters:: arg__2 – PySide2.QtCore.QBitArray
Return type:: PySide2.QtCore.QBitArray

PySide2.QtCore.QBitArray.__ixor__(arg__1)¶

Parameters:: arg__1 – PySide2.QtCore.QBitArray
Return type:: PySide2.QtCore.QBitArray

Performs the XOR operation between all bits in this bit array and other . Assigns the result to this bit array, and returns a reference to it.

The result has the length of the longest of the two bit arrays, with any missing bits (if one array is shorter than the other) taken to be 0.

Example:

a = QBitArray(3)
b = QBitArray(2)
a[0] = 1
a[1] = 0
a[2] = 1
# a: [ 1, 0, 1 ]

b[0] = 1
b[1] = 0
# b: [ 1, 1 ]

a ^= b
# a: [ 0, 1, 1 ]

See also

operator^() operator&=() operator|=() operator~()

PySide2.QtCore.QBitArray.__or__(arg__2)¶

Parameters:: arg__2 – PySide2.QtCore.QBitArray
Return type:: PySide2.QtCore.QBitArray

PySide2.QtCore.QBitArray.__ior__(arg__1)¶

Parameters:: arg__1 – PySide2.QtCore.QBitArray
Return type:: PySide2.QtCore.QBitArray

Performs the OR operation between all bits in this bit array and other . Assigns the result to this bit array, and returns a reference to it.

The result has the length of the longest of the two bit arrays, with any missing bits (if one array is shorter than the other) taken to be 0.

Example:

a = QBitArray(3)
b = QBitArray(2)
a[0] = 1
a[1] = 0
a[2] = 1
# a: [ 1, 0, 1 ]

b[0] = 1
b[1] = 0
# b: [ 1, 1 ]

a |= b
# a: [ 1, 1, 1 ]

See also

operator|() operator&=() operator^=() operator~()

PySide2.QtCore.QBitArray.operator~()

Return type:: PySide2.QtCore.QBitArray

Returns a bit array that contains the inverted bits of this bit array.

Example:

a = QBitArray(3)
b = QBitArray()
a[0] = 1
a[1] = 0
a[2] = 1
# a: [ 1, 0, 1 ]

b = ~a
# b: [ 0, 1, 0 ]

See also

operator&() operator|() operator^()

PySide2.QtCore.QBitArray.resize(size)¶

Parameters:: size – int

Resizes the bit array to size bits.

If size is greater than the current size, the bit array is extended to make it size bits with the extra bits added to the end. The new bits are initialized to false (0).

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

See also

size()

PySide2.QtCore.QBitArray.setBit(i)¶

Parameters:: i – int

Sets the bit at index position i to 1.

i must be a valid index position in the bit array (i.e., 0 <= i < size() ).

See also

clearBit() toggleBit()

PySide2.QtCore.QBitArray.setBit(i, val)

Parameters:

i – int
val – bool

This is an overloaded function.

Sets the bit at index position i to value .

PySide2.QtCore.QBitArray.size()¶

Return type:: int

Returns the number of bits stored in the bit array.

See also

resize()

PySide2.QtCore.QBitArray.swap(other)¶

Parameters:: other – PySide2.QtCore.QBitArray

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

PySide2.QtCore.QBitArray.testBit(i)¶

Parameters:: i – int
Return type:: bool

Returns true if the bit at index position i is 1; otherwise returns false .

i must be a valid index position in the bit array (i.e., 0 <= i < size() ).

See also

setBit() clearBit()

PySide2.QtCore.QBitArray.toggleBit(i)¶

Parameters:: i – int
Return type:: bool

Inverts the value of the bit at index position i , returning the previous value of that bit as either true (if it was set) or false (if it was unset).

If the previous value was 0, the new value will be 1. If the previous value was 1, the new value will be 0.

i must be a valid index position in the bit array (i.e., 0 <= i < size() ).

See also

setBit() clearBit()

PySide2.QtCore.QBitArray.truncate(pos)¶

Parameters:: pos – int

Truncates the bit array at index position pos .

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

See also

resize()

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QBitArray¶

Synopsis¶

Functions¶

Static functions¶

Detailed Description¶