python中实现文本大小写的转换

 

1、小写转换为大写

[root@PC1 test]# ls
a.txt  test.py
[root@PC1 test]# cat a.txt
U R D
S F E
A D E
x v m
e f x
e r d
z d v
[root@PC1 test]# cat test.py    ## 小写转换为大写
#!/usr/bin/python

in_file = open("a.txt", "r")
out_file = open("result.txt", "w")

lines = in_file.readlines()

for i in lines:
    i = i.upper()
    out_file.write(i)

in_file.close()
out_file.close()
[root@PC1 test]# python test.py
[root@PC1 test]# ls
a.txt  result.txt  test.py
[root@PC1 test]# cat result.txt    ## 查看结果
U R D
S F E
A D E
X V M
E F X
E R D
Z D V

 

2、大写转换为小写

[root@PC1 test]# ls
a.txt  test.py
[root@PC1 test]# cat a.txt
U R D
S F E
A D E
x v m
e f x
e r d
z d v
[root@PC1 test]# cat test.py      ## 转换程序
#!/usr/bin/python

in_file = open("a.txt", "r")
out_file = open("result.txt", "w")

lines = in_file.readlines()

for i in lines:
    out_file.write(i.lower())

in_file.close()
out_file.close()
[root@PC1 test]# python test.py
[root@PC1 test]# ls
a.txt  result.txt  test.py
[root@PC1 test]# cat result.txt     ## 查看结果
u r d
s f e
a d e
x v m
e f x
e r d
z d v

 

3、大小写相互转换

[root@PC1 test]# ls
a.txt  test.py
[root@PC1 test]# cat a.txt
U R D
S F E
A D E
x v m
e f x
e r d
z d v
[root@PC1 test]# cat test.py           ## 程序
#!/usr/bin/python

in_file = open("a.txt", "r")
out_file = open("result.txt", "w")

lines = in_file.readlines()

for i in lines:
    out_file.write(i.swapcase())

in_file.close()
out_file.close()
[root@PC1 test]# python test.py
[root@PC1 test]# ls
a.txt  result.txt  test.py
[root@PC1 test]# cat result.txt     ## 转换结果
u r d
s f e
a d e
X V M
E F X
E R D
Z D V