Python string processing and file manipulation

1. Strip function

Strip is trim (crop) the spaces or characters on either side of the string. (Lstrip/rstrip)
Such as:

• Space

'     ABCDBCYESORNOABCBACDD    'print

Abcdbcyesornoabcbacdd

• Character

' ABCDBCYESORNOABCBACDD '   print thestring.strip ('abcd')     #去掉两端的abcd字符yesorno

Question: How to remove the middle space.

thestring = ' Hello python '

s =  '    Hello python   '= s.split ()Print " ". Join (strlist) Hellopython

2. Split

The cut string object is a list.

s =  'age:13, Name:chen, grade:70'= s.split (',' )print  strlist['age:13'  Name: Chen'  grade:70']

3. Join string Join function

s = ['a'' b'c'd '  'print'. Join (s)print' - ' . Join (s) abcda-b-c-d

4, String reversal

s ='python'PrintS[::-1]l=list (s) l.reverse ()PrintL#". Join (L) #注意reverse函数返回值是一个列表Print "'. Join (l) nohtyp['N','o','h','T','y','P']nohtyp

5. Read the data in the file (ReadLines ())

 FR = open (filename) 
 NumberOfLines = Len (Fr.readlines ())          # Get the number of lines in the file 
     Returnmat = Zeros ((numberoflines,3))     & nbsp;   #prepare Matrix to return 
     classlabelvector = []                        #prepare Labels return    
     
     index = 0 
     for line in Fr.readlines (): 
         line = Line.strip () 
          listfromline = line.split (' \ t ') 
         Returnmat[index,: ] = Listfromline[0:3] 
         classlabelvector.append (int (listfromline[-1]) ) 
         Index + = 1 

FR = open (filename) data=[inst.strip (). Split ('\ t' for in Fr.readlins ()]

2014-10-12

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This article link address: Python string processing and file manipulation

Python string processing and file manipulation