详解python中lower和upper函数的使用
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2022-06-06 10:22:21
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今天遇到一点小问题,需要编写一个程序将List 中的无规则英文名按【首字母大写其余部分小写】的方式转换
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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