python regular expression findall

1. Regular expressions?? Regular expressions provide the basis for advanced text pattern matching, extraction, and/or textual search and replace functions, and simply, regular expressions are strings of characters and special symbols. Python supports regular expressions thro

The next step is to make a small example of a reptile with embarrassing hundred. But before you do that, make a detailed collation of the regular expressions in Python. The function of regular expressions in Python crawlers is like the roster used by the teacher at the time of roll-call, which is an essential weapon

: Re. I Ignore case Re. L represents a special character set \w, \w, \b, \b, \s, \s dependent on the current environment Re. M Multi-line mode Re. S is the '. ' and include a newline character ('. ' Do not include newline characters. Re. U represents special character set \w, \w, \b, \b, \d, \d, \s, \s dependent on Unicode character Property database Re. X to increase readability, ignore spaces and comments after ' # ' The following two usage results are the sam

parameter indicates the number of replicas. The default value is 0, indicating that each matching item is replaced. Re. sub also allows the use of functions to replace matching items for complex processing. For example, re. sub (r '\ S', lambda m:' ['+ m. group (0) + ']', text, 0); replace the space ''in the string with '[]'. Re. split You can use re. split to split a string, such as re. split (r '\ s +', text). the string is split into a word list by space. Re.

, such as Re. Split (r '\ s +', text). The string is split into a word list by space. Re. findall Re. findall can obtain all matching strings in the string. For example, re. findall (R' \ W * oo \ W * ', text); obtains all words containing 'oo' in a string. Re. Compile You can compile a regular

Summary In regular expressions, if a character is given directly, it is exactly the exact match. {m,n}?Repeat to the previous character m n , and take as few cases as possible in the string ‘aaaaaa‘ , a{2,4} matching 4 a , but a{2,4}? only 2 matches a . ^Represents the beginning of a row, ^\d indicating that a number must begin.$Represents the end of a line, indicating that it \d$ must end with a number.You may have noticed that you

In the previous articles we used the Python urllib module and did some work on the Web page. Now introduce a very powerful tool-the regular expression. In telling the regular, I refer to the book "Proficient in Regular expression

In the face of a lot of messy code inclusion text How can we extract it to organize it? Let's start with a very powerful tool, Regular Expressions！ 1. Understanding Regular Expressions A regular expression is a logical formula for a string operation, which is a "rule string" that is used to express a filter logic for

Search lines that start with the string "From:"Import= open ('mbox-short.txt') for in = Line.rstrip () if re.search ('ˆfrom:', line): Print Line //match any of the strings "From:", "FXXM:", "f12m:", or "[emailprotected]:" 1 import re 2 hand = open ( mbox-short.txt ) 3 for line in hand: 4 line = Line.rstrip () 5 if re.search ( ˆf.. M: 6 print line //search lines that start with ' from: ', followed by one or more characters (". +"), follow Ed by an at-sign 1

Re --- Python Regular Expression Module Re is the most common Regular Expression module in Python. Common methods include compile, match, findall, finditer, search, split, and sub. Whe

object function to get a matching expression. Groups () prints the entire tuple group () prints the entire string, group (1) prints the first element group (1,3) print 第1-3个 element span() matches the position [start, end] Retrieving and replacingThe Python re module provides re.sub to replace matches in a string.string, count=0) Pattern: The pattern string in the reg