Shulou(Shulou.com)06/02 Report--

In view of how to use the re module in python, this article introduces the corresponding analysis and solution in detail, hoping to help more partners who want to solve this problem to find a more simple and feasible method.

Introduction to re Modul

Re module is the official module of python. Once python is installed, you can import re it.

The re module encapsulates many functions about regular expressions, which are used to achieve all the functions of regular expressions. Re module is used in many situations, so we must learn more and practice more, so that we can really master the re module.

Common function findall

Parameter description:

Re.findall (pattern, string, flags=0)

Patten: regular expression.

String: the string to match.

Flags: flag bit that controls how regular expressions are matched, such as case sensitivity, multiline matching, and so on.

Return value:

Match starts from the beginning of the string, and there is no result from the match to the end. If you return None; match to the result, you can return a list of strings (multiple results can be matched).

Purpose:

Find or extract content by regular expression from a string.

Case study:

Import reresult = re.findall ("123abc567def98') print (result) out: ['123,' 567, '98'] search

Parameter description:

The parameters are exactly the same as findall.

Return value

Match starts at the beginning of the string, and there is no result from the match to the end. If you return None; match to the result, the re.Match object is returned (only one result is matched).

The first value of the span of the re.Match object is the first successful match position, and the second value is 1 bit after the match ends. Match saves the matching content.

Use the variable name .group () method to extract the matching results.

Purpose:

Find out if there is anything in the string that matches the regular expression.

Case study:

Result1 = re.search ("123abc567def98') print (result1) print (result1.group ()) result2 = re.search ('\ dcuttledge" abc567def98') print (result2) print (result2.group ()) out: 123567match

Parameter description:

The parameters are exactly the same as findall.

Return value:

The return value is basically the same as search. The difference is that if match fails to match, None; will be returned, while search will continue to match backwards until the match succeeds or ends.

Purpose:

Verify that the content entered by the user conforms to the regular expression.

Case study:

Result1 = re.match ("123abc567def98') print (result1) print (result1.group ()) result2 = re.match ('\ dblemale" abc567def98') print (result2) if result2: # the value of result2 is None when matching fails, and printing group will report an error. Print (result2.group ()) out:123Nonesplit

Parameter description:

Re.split (pattern, string, maxsplit=0, flags=0)

Patten: regular expression.

String: the string to match.

Maxsplit: cutting parameter. The default value of 0 means there is no limit on the number of times. Parameters can be passed to specify the number of cuts.

Flags: flag bit that controls how regular expressions are matched, such as case sensitivity, multiline matching, and so on.

Return value:

The return value is a list of strings, and there may be empty character elements.

Purpose:

Cut the string according to the regular expression.

Case study:

Result1 = re.split ('\ dharma') print (result1) result2 = re.split ('[aafuz]', '123abc567def98ghi') print (result2) result3 = re.split ('\ wit') print (result3) out: ['', 'abc',' def', 'ghi'] [' 123abc567def98ghi`] ['123abc567def98ghi`,'] [','] ',']

Add:

Because re.split cuts generate empty strings, there is often a need to remove empty strings from the list, so add some code to remove empty strings from the list.

Result1 = list (filter (lambda x: X, result1)) result2 = list (filter (lambda x: X, result2)) result3 = list (filter (lambda x: X, result2)) print (result1) print (result2) print (result3) out: ['abc',' def', 'ghi'] [' 123, '567,' 98] [] this is the answer to the question about how to use the re module in python. I hope the above can be helpful to you. If you still have a lot of questions to solve, you can follow the industry information channel to learn more about it.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.