Python string usage learn ing

#!/usr/bin/env python#-*- coding:utf-8 -*-##################################################### # author: sunfx   [email protected]# last modified:  2014/11 /11# filename:  string.py# q  q   Group:   236147801############## ###################################### #import  reimport stringstr =  ' i love  Python ' #1. Generates a 20-character length Print str.center () #2. Aligns print str.ljust #3. Word Aligns alignment print str.rjust (20) # 4.str right-aligned, padding 0print str.zfill (#5) on the left. All characters uppercase Print str.upper () #6. All characters go to lowercase print str.lower () #7. Capitalize the first letter of all words s =  ' thi quick brown fox jumped over the lazy   dog. ' Print sprint string.capwords (s) #8. Capitalization print str.swapcase () #9. The delimiter is marked, the first character is capitalized, and the remaining lowercase print  Str.title () #10. Template conversion   character substitution   more efficient than replace Leet = string.maketrans (' Abegiloprstz ', ' 463611092572 ' ) s =  ' Thi quick brown fox jumped over the lazy  dog. ' Print sprint s.translate (leet) str =  ' 0123 ' #11. Are all letters and numbers, and at least one character Print str.isalnum () # 12. Are all numbers and at least one character print str.isdigit () #13. Determines whether all letters are full, and at least one character print str.isalpha () #14. Determine if it is lowercase, When all are lowercase and numbers together, it is also judged as Trueprint str.islower () #15. Determines whether it is a white space character, and has at least one character print str.isspace () #16. Determines whether a character is print str.startswith (' str ') at the beginning of str #17. The interpretation character is terminated with Str print str.endswith (' str ') str =  ' String 1eamd ' #18. Look for character, no return-1, is responsible for returning to the first matching index print str.find (' a ') #19. Find character, no return-1, is responsible for returning to the last matched index print  str.rfind (' a ') #20. To find the character, if there is no error, it is the responsibility to return to the first matching index print str.index (' s ') #21. Find the character, no error, and be responsible for returning to the last matching index print  str.rindex (' s ') #22. Find the number of occurrences of a string in a character print str.count (' s ') #23. Replace the matching character print str.replace (' s ', ' A ') #24. Removes the string-to-match character, which is commonly used to remove the carriage return Print str.strip (' n ') #25. Delete the matching character print str.lstrip (' n ') on the left #26. Delete the matching characters on the right print  Str.rstrip (' n ') #27. Turn tabs into spaces str =  '      tab ' Print str.expandtabs () str =  ' I'm learning ' #28. The decoding process, decoding utf-8 to Unicodeprint str.decode (' Utf-8 ') #29. Encoding process, encoding Unicode to Gbkprint str.decode (' Utf-8 '). Encode (' GBK ') #30. Speak Unicode encoding utf-8print  Str.decode (' Utf-8 '). Encode (' Utf-8 ') #31. Character segmentation str =  ' learn string ' print  '-'. Join (str) #32. What is the split print str.split ('   ') #33. Template template values = {' var ': ' foo '}t = string. Template ("" "    Variale       :  $var      escape        : $$    variable  in text: ${var}iable "" ") print  ' TEMPLATE: ', T.substitute (values) s = " ""      variale       : % (Var) s     escape        : %%    variable in  text: % (Var) siable "" "print ' Interpolation: ', s % values#34.template  exception handling t = string. Template ("$var  is here but  $missing  is not provided") try:     print  ' substitute ()  : ', T.substitute (values) except keyerror, err:print  ' ERROR: ', STR (ERR) print  ' Safe_substitute (): ', T.safe_substitute (values)   #36. Advanced Template template_text =  "     delimiter : %%    replaced  : %with_ Underscore    ignored   : %notundersocred ' #37. You can customize the templace  Conversion rules d = {  ' with_underscore ': ' Replaced ',       ' notundersocred ': ' Not replaced '}class mytemplate (string. Template):d elimiter =  '% ' idpattern =  ' [a-z]+_[a-z]+ ' T = mytemplate (template_text ) print  ' Modified id pattern: ' Print t.safe_substitute (d) #38. Customize more complex rules t = string. Template (' $var ') Print t.pattern.pattern '     \$ (?:        (? p<escaped>\$)  |   # Escape sequence of two delimiters  #忽略的分隔符        (? p<named>[_a-z][_a-z0-9]*)       |   # delimiter  and a python identifier  #python分隔符的标识 (i.e. variable)       {(? p<braced>[_a-z][_a-z0-9]*)}   |   # delimiter and a  braced identifier  #分隔符和一个支撑的标识        (? p<invalid>)               #  other ill-formed delimiter exprs  #无效的     ) ' Class mytemplate ( String. Template):d elimiter =  ' {'   #定义转义符pattern  = r ' \{\{(??:     (? P<escaped>\{\{)  |     (? p<named>[_a-z][_a-z0-9]*) \}\} |     (? p<braced>[_a-z][_a-z0-9]*) \}\} |     (? p<invalid>)    ' t = mytemplate ('     {{{{     {{var}} "print t.template  #查看template的值print   ' MATCHES: ', T.pattern.findall (t.template)   #查看正则匹配到的字符print   ' substiituted: ', T.safe_substitute (var= ' replacement ')   #使用替换print   mytemplate.delimiter   #查看mytemplate转义符print  string. template.delimiter   #查看string转义符 #http://legacy.python.org/dev/peps/pep-0292/#格式化段落 #39. Fill paragraph     left-aligned, first line indent, Row Hollow cell continues to retain import textwrapsample_text =  '      The  Textwrap modulde can be used to format text for output in      situations where pretty-parinting is desired. It offers      programmatic functionality similar to the  paragraph wrapping     or filling features found in  Myany text editors. " print  ' no dedent:\n ' Print textwrap.fill (sample_text,width=50) #40. Remove existing indents (remove all spaces in the line) Dedemted_text  = textwrap.dedent (Sample_text) print dedemted_text#41. Combine fill and dedent  to specify the width of the output text Dedemted_text  = textwrap.dedent (Sample_text). Strip () print dedemted_textfor width in [45,70]: print  '%d columns:\n '  % widthprint textwrap.fill (dedemted_text,width=width) print#42. Hanging indent Print textwrap.fill (dedemted_text,                 initial_indent= ',   #定义文本第一行缩进的长度                  subsequent_indent= '      '  * 4,   #定义其他行的缩进                  width=50  #定义文本长度, default 75)

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Python string usage learn ing