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This article mainly introduces "what is the compile function syntax of Python". In daily operation, I believe that many people have doubts about the syntax of Python compile function. The editor has consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful to answer the doubt of "what is the compile function syntax of Python?" Next, please follow the editor to study!

Compile function

The compile function is used to compile regular expressions and generate a regular expression (Pattern) object for use by the match () and search () functions.

The syntax format is:

Re.compile (pattern [, flags])

Parameters:

Pattern: a regular expression in string form

Flags is optional, indicating matching patterns, such as ignoring case, multiline mode, etc. The specific parameters are:

Re.I ignores case

Re.L indicates that the special character set\ w,\ W,\ b,\ B,\ s,\ S depends on the current environment

Re.M multiline mode

Re.S means'. 'and any character including a newline character ('. 'excluding newline characters)

Re.U represents the special character set\ w,\ W,\ b,\ B,\ d,\ D,\ s,\ S depending on the Unicode character attribute database

Re.X ignores spaces and comments after'#'to increase readability

Example

> import re

> pattern = re.compile (r'\ dflowers') # is used to match at least one number

> m = pattern.match ('one12twothree34four') # Lookup header, no match

> print (m)

None

> m = pattern.match ('one12twothree34four', 2,10) # starting from the position of' e', there is no match.

> print (m)

None

> m = pattern.match ('one12twothree34four', 3,10) # starting from the position of' 1', it matches exactly

> print (m) # returns a Match object > m.group (0) # 0 can be omitted

'12'

> m.start (0) # 0 can be omitted

three

> m.end (0) # 0 can be omitted

five

> m.span (0) # 0 can be omitted

(3, 5)

Above, a Match object is returned when the match is successful, where:

Group ([group1, …]) Method is used to get one or more grouped matching strings, and when you want to get the entire matching substring, you can directly use group () or group (0)

The start ([group]) method is used to obtain the starting position of the grouped matching substring in the entire string (the index of the first character of the substring). The default value of the parameter is 0.

The end ([group]) method is used to get the end position of the grouped matching substring in the entire string (the index of the last character of the substring + 1). The default value of the parameter is 0.

The span ([group]) method returns (start (group), end (group)).

At this point, the study of "what is the syntax of the compile function of Python" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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