截取字符，替换字符

目的：proxy_1-0-58-BRANCH ---> proxy1.0.58

1. python

# python
_str='proxy_1-0-58_BRANCH'
''.join('.'.join(_str.split('-')).split('_'))[:-6]

切片函数split(str="", num=string(count(str)))

_str.split('-', 1) #['proxy_1', '0-58-BRANCH']

切片对象 class slice(start, stop[, step])

myslice = slice(2)
_list = [1,2,3,4]
print _list[myslice]  # 1,2

2. SHELL

# shell
_str='proxy_1-0-58_BRANCH'
echo ${_str:0:-6} | sed 's\-\.\g' | sed 's\_\\g'

sed使用：插入删除替换文本
https://www.jb51.net/article/56563.htm
https://www.cnblogs.com/kinga/p/5772566.html

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