字符串变量初始化

import re


# 解析字符串中全局变量并进行替换
def resolve_global_var(pre_resolve_var, global_var_dic, global_var_regex='\${.*?}',
                       match2key_sub_string_start_index=2, match2key_sub_string_end_index=-1):
    '''
    :param pre_resolve_var: 准备进行解析的变量<str>
    :param global_var_dic: 全局变量字典<dict>
    :param global_var_regex: 识别全局变量正则表达式<str>
    :param match2key_sub_string_start_index: 全局变量表达式截取成全局变量字典key值字符串的开始索引<int>
    :param match2key_sub_string_end_index: 全局变量表达式截取成全局变量字典key值字符串的结束索引<int>
    :return: 解析后的变量<str>
    '''

    if not isinstance(pre_resolve_var, str):
        raise TypeError('pre_resolve_var must be str！')

    if not isinstance(global_var_dic, dict):
        raise TypeError('global_var_dic must be dict！')

    if not isinstance(global_var_regex, str):
        raise TypeError('global_var_regex must be str！')

    if not isinstance(match2key_sub_string_start_index, int):
        raise TypeError('match2key_sub_string_start_index must be int！')

    if not isinstance(match2key_sub_string_end_index, int):
        raise TypeError('match2key_sub_string_end_index must be int！')

    # re_global_var = re.compile(global_var_regex)

    def global_var_repl(match_obj):
        start_index = match2key_sub_string_start_index
        end_index = match2key_sub_string_end_index
        match_value = global_var_dic.get(match_obj.group()[start_index:end_index])
        return match_value if match_value else match_obj.group()

    resolved_var = re.sub(pattern=global_var_regex, string=pre_resolve_var, repl=global_var_repl)
    return resolved_var
global_var_dic ={
    "username":"xiaoming"
}
blist =[1,2,3]
alist = '{"name":"${username}","age":blist[1]}'
alist= resolve_global_var(alist,global_var_dic)
print(alist)
c = eval(alist)
print(c)