python 中 #-*-coding: UTF-8 -*-的作用

#-*-coding: UTF-8 -*- 解决python2 中 中文乱码报错的问题

001、

[root@pc1 test1]# ls
a.fa  test.py
[root@pc1 test1]# cat a.fa    ## 测试数据
>chr1 xxx
aaaggg
eeee
>chr2 yyy
dddddgggg
dedeee
>chr3 zzz
eeeeeexxxx
[root@pc1 test1]# cat test.py     ## 测试程序
#!/usr/bin/python

# 测试                             ## 加中文注释
in_file = open("a.fa", "r")
out_file = open("result.fa", "w")

for i in in_file:
        i = i.strip()
        if i.startswith(">"):
                out_file.write(i + "\n")

in_file.close()
out_file.close()
[root@pc1 test1]# python2 test.py       ## python2 报错
  File "test.py", line 3
SyntaxError: Non-ASCII character '\xe6' in file test.py on line 3, but no encoding declared; see http://www.python.org/peps/pep-0263.html for details
[root@pc1 test1]# python3 test.py       ## python3 没有问题
[root@pc1 test1]# ls
a.fa  result.fa  test.py

脚本中增加：#-*-coding: UTF-8 -*-

[root@pc1 test1]# ls
a.fa  test.py
[root@pc1 test1]# cat test.py
#!/usr/bin/python
#-*-coding: UTF-8 -*-              ## 增加改行

# 测试
in_file = open("a.fa", "r")
out_file = open("result.fa", "w")

for i in in_file:
        i = i.strip()
        if i.startswith(">"):
                out_file.write(i + "\n")

in_file.close()
out_file.close()
[root@pc1 test1]# python2 test.py     ## python2运行没有问题
[root@pc1 test1]# ls
a.fa  result.fa  test.py