python字串函數，python字串

python字串函數，python字串

1，首字母大寫

>>> s = 'ghostwu'>>> s.capitalize()'Ghostwu'

2，replace，替換

>>> s = 'my name is ghostwu, age is 20'>>> s'my name is ghostwu, age is 20'>>> s.replace( '20', '30' )'my name is ghostwu, age is 30'>>> s'my name is ghostwu, age is 20'>>> 

查協助

>>> help( str.replace )

如果是面向過程的函數用法，直接help( 函數名 )，如help( abs )

用法說明：

replace(...)
S.replace(old, new[, count]) -> string

Return a copy of string S with all occurrences of substring
old replaced by new. If the optional argument count is
given, only the first count occurrences are replaced.

接受3個參數，第一個需要替換的字元，第二個用什麼字元去替換，第三個替換的次數，如果不傳，預設全部替換

1 >>> str = '121212'2 >>> str.replace( '1', 'g' )3 'g2g2g2'4 >>> str.replace( '1', 'g', 1 )5 'g21212'6 >>> str.replace( '1', 'g', 2 )7 'g2g212'8 >>> str.replace( '1', 'g', 3 )9 'g2g2g2'

3，split：切割

 1 >>> ip='127.0.0.1' 2 >>> ip 3 '127.0.0.1' 4 >>> ip.split( '.' ) 5 ['127', '0', '0', '1'] 6 >>> ip.split( '.', 1 ) 7 ['127', '0.0.1'] 8 >>> ip.split( '.', 2 ) 9 ['127', '0', '0.1']10 >>> ip.split( '.', 3 )11 ['127', '0', '0', '1']12 >>> 

4，用string模組，用法如下：

1 >>> import string2 >>> help( string.capitalize )3 4 >>> s = 'ghostwu'5 >>> string.capitalize( s )6 'Ghostwu'

 1 >>> import string 2 >>> s = 'my name is ghostwu, age is 20' 3 >>> string.replace( s, '20', '30' ) 4 'my name is ghostwu, age is 30' 5 >>> ip 6 '127.0.0.1' 7 >>> string.split( ip, '.' ) 8 ['127', '0', '0', '1'] 9 >>> string.split( ip, '.', 1 )10 ['127', '0.0.1']11 >>> 

5，filter：過濾， 利用這個函數，篩選出一個序列的偶數

 1 >>> def isEven( n ): 2 ...     if n % 2 == 0: 3 ...             return True 4 ...  5 >>> isEven( 10 ) 6 True 7 >>> isEven( 3 ) 8 >>> range( 10 ) 9 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]10 >>> l = range( 10 )11 >>> filter( isEven, l )12 [0, 2, 4, 6, 8]13 >>>