详解python中lower和upper函数的使用

一开始的思路是编写一个函数将每个名字字符串【str】进行处理，如何用map进行批处理

不得不说，大方向的思路是正确的，但在细节的处理上出了些问题

最开始我是这样写名字处理函数的：

[python] view plain copy
def change (name)  
    result = name[0].upper()  
    for a in name[1:len(name)]:  
        result = result + a.lower()

然后运行会报错

[python] view plain copy
E:\PythonFile>python practice.py  
  File "practice.py", line 6  
    for a in name(1:len(name)-1) :  
                   ^  
SyntaxError: invalid syntax  
  
E:\PythonFile>python practice.py  
Traceback (most recent call last):  
  File "practice.py", line 11, in <module>  
    name_li = map (change, name_list)  
  File "practice.py", line 6, in change  
    for a in name(1,len(name)-1) :  
TypeError: 'str' object is not callable  
  
E:\PythonFile>python practice.py  
Traceback (most recent call last):  
  File "practice.py", line 9, in <module>  
    name_li = map (change, name_list)  
  File "practice.py", line 5, in change  
    name[0] = name[0].upper()  
TypeError: 'str' object does not support item assignment  
  
E:\PythonFile>python practice.py  
Traceback (most recent call last):  
  File "practice.py", line 10, in <module>  
    name_li = map (change, name_list)  
  File "practice.py", line 6, in change  
    name[0] = tmp  
TypeError: 'str' object does not support item assignment  
  
E:\PythonFile>python  
Python 2.7.9 (default, Dec 10 2014, 12:24:55) [MSC v.1500 32 bit (Intel)] on win  
32  
Type "help", "copyright", "credits" or "license" for more information.  
>>> l = 'zxcv'  
>>> print l[0]  
z  
>>> print l[0].upper  
<built-in method upper of str object at 0x02148740>  
>>> print l[0].upper()  
Z  
>>> z  
Traceback (most recent call last):  
  File "<stdin>", line 1, in <module>  
NameError: name 'z' is not defined  
>>> ^Z  
  
  
E:\PythonFile>python practice.py  
Traceback (most recent call last):  
  File "practice.py", line 9, in <module>  
    name_li = map (change, name_list)  
  File "practice.py", line 6, in change  
    name[0] = tmp  
TypeError: 'str' object does not support item assignment  
  
E:\PythonFile>python practice.py  
Traceback (most recent call last):  
  File "practice.py", line 13, in <module>  
    name_li = map (change, name_list)  
  File "practice.py", line 5, in change  
    tmp = chr(name[0])  
TypeError: an integer is required

试过几次后发现大致意思是对字符串的处理不能这么做，于是查了upper（）和lower()的用法，发现这两个函数就是直接作用于str的，所以根本不需要这么麻烦。

修改后：

[python] view plain copy
# practice.py  
# Change the first char in every name from lower type to upper type  
  
def change (name):  
    result =  name[0:1].upper()+name[1:len(name)].lower()  
    return result  
  
name_list = ['kzd','ysy','kcw','scr','ky']  
name_li = map (change, name_list)  
print name_l

运行结果：

[python] view plain copy
E:\PythonFile>python practice.py  
['Kzd', 'Ysy', 'Kcw', 'Scr', 'Ky']

错误在于我企图对字符串中的元素进行赋值替换，这是不允许的。

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