QRegExpValidator

The QRegExpValidator class is used to check a string against a regular expression. More…

Synopsis

Functions

• def regExp ()

• def setRegExp (rx)

Signals

• def regExpChanged (regExp)

Detailed Description

QRegExpValidator uses a regular expression (regexp) to determine whether an input string is Acceptable , Intermediate , or Invalid . The regexp can either be supplied when the QRegExpValidator is constructed, or at a later time.

When QRegExpValidator determines whether a string is Acceptable or not, the regexp is treated as if it begins with the start of string assertion (^ ) and ends with the end of string assertion ($ ); the match is against the entire input string, or from the given position if a start position greater than zero is given.

If a string is a prefix of an Acceptable string, it is considered Intermediate . For example, “” and “A” are Intermediate for the regexp [A-Z][0-9] (whereas “_” would be Invalid ).

For a brief introduction to Qt’s regexp engine, see QRegExp .

Example of use:

# regexp: optional '-' followed by between 1 and 3 digits
rx = QRegExp("-?\\d{1,3}")
validator = QRegExpValidator(rx, self)

edit = QLineEdit(self)
edit.setValidator(validator)

Below we present some examples of validators. In practice they would normally be associated with a widget as in the example above.

# integers 1 to 9999
rx = QRegExp("[1-9]\\d{0,3}")
# the validator treats the regexp as "^[1-9]\\d{0,3}$"
v = QRegExpValidator(rx, 0)
pos = 0

s = "0"
v.validate(s, pos)    # returns Invalid
s = "12345"
v.validate(s, pos)    # returns Invalid
s = "1"
v.validate(s, pos)    # returns Acceptable

rx.setPattern("\\S+")            # one or more non-whitespace characters
v.setRegExp(rx)
s = "myfile.txt"
v.validate(s, pos) # Returns Acceptable
s = "my file.txt"
v.validate(s, pos) # Returns Invalid

# A, B or C followed by exactly five digits followed by W, X, Y or Z
rx.setPattern("[A-C]\\d{5}[W-Z]")
v.setRegExp(rx)
s = "a12345Z"
v.validate(s, pos)        # Returns Invalid
s = "A12345Z"
v.validate(s, pos)        # Returns Acceptable
s = "B12"
v.validate(s, pos)        # Returns Intermediate

# match most 'readme' files
rx.setPattern("read\\S?me(\.(txt|asc|1st))?")
rx.setCaseSensitive(false)
v.setRegExp(rx)
s = "readme"
v.validate(s, pos) # Returns Acceptable
s = "README.1ST"
v.validate(s, pos) # Returns Acceptable
s = "read me.txt"
v.validate(s, pos) # Returns Invalid
s = "readm"
v.validate(s, pos) # Returns Intermediate

See also

QRegExp QIntValidator QDoubleValidator Settings Editor Example

class PySide2.QtGui.QRegExpValidator([parent=None])

PySide2.QtGui.QRegExpValidator(rx[, parent=None])

param parent:

PySide2.QtCore.QObject

param rx:

PySide2.QtCore.QRegExp

Constructs a validator with a parent object that accepts any string (including an empty one) as valid.

Constructs a validator with a parent object that accepts all strings that match the regular expression rx .

The match is made against the entire string; e.g. if the regexp is [A-Fa-f0-9]+ it will be treated as ^[A-Fa-f0-9]+$ .

PySide2.QtGui.QRegExpValidator.regExp()

Return type:

PySide2.QtCore.QRegExp

This property holds the regular expression used for validation.

By default, this property contains a regular expression with the pattern .* that matches any string.

PySide2.QtGui.QRegExpValidator.regExpChanged(regExp)

Parameters:

regExp – PySide2.QtCore.QRegExp

PySide2.QtGui.QRegExpValidator.setRegExp(rx)

Parameters:

rx – PySide2.QtCore.QRegExp

This property holds the regular expression used for validation.

By default, this property contains a regular expression with the pattern .* that matches any string.