Common python string handling

1. String merging and linking

Plus sign Merge

Join method Merge

2, multiply and slice

Line= ' * ' *30

Print (line)

>>******************************

Slice:

Consequence[start_index:end_index:step]

Represents the first element, the positive index position defaults to 0, and the negative index position defaults to-len (consequence)

End_index represents the last element object, the positive index position defaults to Len (consequence)-1; Negative index position defaults to 1

PrintStr[0:3]#Intercept first-to-third-digit charactersPrintstr[:]#truncate all characters of a stringPrintStr[6:]#Intercept the seventh character to the end of thePrintSTR[:-3]#intercept from the beginning to the third character before the third one does not includePrintSTR[2]#interception of the third characterPrintSTR[-1]#Intercept the first character of the countdownPrintSTR[::-1]#create a string opposite to the original string orderPrintSTR[-3:-1]#the characters preceding the last third to the last digit do not include the last digit of the penultimate character.PrintStr[-3:] Intercept the last third to the endPrintSTR[:-5:-3] Reverse Intercept

Three-string segmentation

Common split, with split, does not support multiple separators

A complex separation

R means no escaping, the delimiter can be, or, a space followed by 0 additional spaces, and then the pattern to split

Split (string[, Maxsplit]) | Re.split (Pattern, string[, Maxsplit]):

Returns a list after splitting a string by a substring that can be matched. The maxsplit is used to specify the maximum number of splits and does not specify that all will be split.

Import re

p = re.compile (R ' \d+ ')
Print p.split (' One1two2three3four4 ')

# # # output # #
# [' One ', ' one ', ' one ', ' three ', ' four ',

4. Handling of the beginning and end of a string

For example, find out what a file name begins with or ends with

Filename= ' trace.h '

Print (Filename.endwith (' h '))

>>true

Print (Filenam.startwith (' Trace '))

>>true

5. Finding and matching strings

General Search:

Finds a string inside a long string, returns the index of the string that contains it, or returns 1

Str.find (' xxxx ')

Complex matching:

Using Import re

6. Substitution of strings

Normal Replacement: Replace

Str.replace (' replaced ', ' replace ')

Complex replacements

Using regular matching Re.sub

7. Remove some characters from the string

Remove whitespace for text processing such as reading a line from a file, and then removing the spaces on each line, tab or line break

Line= ' Congratulations, you guessed it. '

Print (Line.strip ())

>>congratulations, you guessed it.

Note: The space inside the string cannot be removed , to remove the need to use the RE module

Complex text cleanup can take advantage of str.translate,

First build a conversion table, table is a translation table, indicating the ' t ' o ' turn into uppercase ' t ' o ',

Then remove ' 12345 ' from the Old_str, then the remaining strings are translated by the table.

Common python string handling