python字符串的方法

python字符串的方法

############7个基本方法############

1：join

 def join(self, ab=None, pq=None, rs=None): # real signature unknown; restored from __doc__
     """
     Concatenate any number of strings.

     The string whose method is called is inserted in between each given string.
     The result is returned as a new string.

     Example: '.'.join(['ab', 'pq', 'rs']) -> 'ab.pq.rs'
     """
     可以向字符串插入 标识符 标点 字母等连接

test=("qweqweqw")
v="_".join(test)
print(v)

q_w_e_q_w_e_q_w

test=(['as','df','as'])
v="_".join(test)
print(v)

as_df_as

　　

2：split（正则）

 split(self, *args, **kwargs): # real signature unknown
     """
     Return a list of the words in the string, using sep as the delimiter string.

       sep
         The delimiter according which to split the string.
         None (the default value) means split according to any whitespace,
         and discard empty strings from the result.
       maxsplit
         Maximum number of splits to do.
         -1 (the default value) means no limit.
     """
 全分割 从第一个逐一扫描字符串寻找所选字符 从字符串中找到该字符位置开始分割 （所选字符消失）

test=("asdfasdfasdfsadfsdf")
v=test.split("f")
print(v)

['asd', 'asd', 'asd', 'sad', 'sd', '']

test=("asdfasdfasdf")
v=test.split("s",2,)
print(v)

['a', 'dfa', 'dfasdf']

　　

3：find

find(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
    """
    S.find(sub[, start[, end]]) -> int

    Return the lowest index in S where substring sub is found,
    such that sub is contained within S[start:end].  Optional
    arguments start and end are interpreted as in slice notation.

    Return -1 on failure.
    """
    return 0
从左向右查找所定义的字符 显示首个该字符的索引（下标）；find（字符，开始索引，结束索引）

test=("asdfasdfasdfsadfsdf")
v=test.find("f")
print(v)

3

test=("asdfasdfasdfsadfsdf")
v=test.find("f",5,15)
print(v)

7

　　

4：strip

strip(self, *args, **kwargs): # real signature unknown
    """
    Return a copy of the string with leading and trailing whitespace remove.

    If chars is given and not None, remove characters in chars instead.
    """
清除字符串两边的空格

test=("  asdfasdfas   dfsadfsdf   ")
v=test.strip()
print(v)

asdfasdfas    dfsadfsdf

　　

5：upper

upper(self, *args, **kwargs): # real signature unknown
    """ Return a copy of the string converted to uppercase. """
字符串全大写

test=("asdfasdfasdfsadfsdf")
v=test.upper()
print(v)

ASDFASDFASDFSADFSDF

　　

6：lower

lower(self, *args, **kwargs): # real signature unknown
    """ Return a copy of the string converted to lowercase. """
    pass
字符串全小写

test=("ASDFASDFASDFSADFSDF")
v=test.lower()
print(v)

asdfasdfasdfsadfsdf

　　

7：replace

replace(self, *args, **kwargs): # real signature unknown
    """
    Return a copy with all occurrences of substring old replaced by new.

      count
        Maximum number of occurrences to replace.
        -1 (the default value) means replace all occurrences.

    If the optional argument count is given, only the first count occurrences are
    replaced.
    """
替换所选字符   replace（“文本内的字符”，“想要替换文本的字符”，“替换的数量”）

test=("ASDFASDFASDFSADFSDF")
v=test.replace("ASD","aaa",1)
print(v)

aaaFASDFASDFSADFSDF

test=("ASDFASDFASDFSADFSDF")
v=test.replace("ASD","aaa")
print(v)

aaaFaaaFaaaFSADFSDF