bat中IF NOT "%Choice%"=="" SET Choice=%Choice:0,1%

bat中IF NOT "%Choice%"=="" SET Choice=%Choice:0,1%
bat中IF NOT "%Choice%"=="" SET Choice=%Choice:0,1%

bat中IF NOT "%Choice%"=="" SET Choice=%Choice:0,1%
如果%Choice%不为空 就把%Choice:~0,1%赋给Choice
注释：if 如果not 取反%Choice% 变量名== 等于set 设置,构成
Choice 变量名= 赋值%Choice:~0,1% 配置参数