PySide.QtGui.QRegExpValidator class is used to check a string against a regular expression.
PySide.QtGui.QRegExpValidator uses a regular expression (regexp) to determine whether an input string is Acceptable , 中间体 ，或 Invalid . The regexp can either be supplied when the PySide.QtGui.QRegExpValidator is constructed, or at a later time.
当 PySide.QtGui.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 中间体 . For example, “” and “A” are 中间体 for the regexp [A-Z][0-9] (whereas ” _ ” would be Invalid ).
For a brief introduction to Qt's regexp engine, see PySide.QtCore.QRegExp .
用法范例：
# 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}$"
v = QRegExpValidator(rx, 0)
pos = 0
s = "0"
v.validate(s, pos) # returns Invalid
s = "12345"
v.validate(s, pos) # returns Invalid
s = "1"
v.validate(s, pos) # returns Acceptable
rx.setPattern("\\S+") # one or more non-whitespace characters
v.setRegExp(rx)
s = "myfile.txt"
v.validate(s, pos) # Returns Acceptable
s = "my file.txt"
v.validate(s, pos) # Returns Invalid
# A, B or C followed by exactly five digits followed by W, X, Y or Z
rx.setPattern("[A-C]\\d{5}[W-Z]")
v.setRegExp(rx)
s = "a12345Z"
v.validate(s, pos) # Returns Invalid
s = "A12345Z"
v.validate(s, pos) # Returns Acceptable
s = "B12"
v.validate(s, pos) # Returns Intermediate
# match most 'readme' files
rx.setPattern("read\\S?me(\.(txt|asc|1st))?")
rx.setCaseSensitive(false)
v.setRegExp(rx)
s = "readme"
v.validate(s, pos) # Returns Acceptable
s = "README.1ST"
v.validate(s, pos) # Returns Acceptable
s = "read me.txt"
v.validate(s, pos) # Returns Invalid
s = "readm"
v.validate(s, pos) # Returns Intermediate
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构造验证器采用 parent object that accepts any string (including an empty one) as valid.
构造验证器采用 parent object that accepts all strings that match the regular expression rx .
The match is made against the entire string; e.g. if the regexp is [A-Fa-f0-9]+ it will be treated as ^[A-Fa-f0-9]+$ .
| 返回类型： | PySide.QtCore.QRegExp |
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This property holds the regular expression used for validation.
By default, this property contains a regular expression with the pattern .* that matches any string.
| 参数： | rx – PySide.QtCore.QRegExp |
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This property holds the regular expression used for validation.
By default, this property contains a regular expression with the pattern .* that matches any string.