Regular Expressions 101

Community Patterns

MathExpersion-PTA-Homework_11

0

Regular Expression
ECMAScript (JavaScript)

/
([+\-*\/]{2,}\d+)|(\([+\*\/])|((?<![\d\)])[+\*\/]\()|(\)[+\-\*\/](?![\d\()]))|((?<![\d\)])(?=[+\*\/]\d+))|(\(\))|(\d+[+\-\*\/](?![\d(]))|((?<![\d\+\-\*\/])\([+\-\*\/])|((?<![\d])[+\-\*\/]\))
/
gm

Description

校验数学表达式:主要功能如下: 连续的运算符,例如--5 运算符为正数时,其符号+必须省略,例如+2+4定义为非法,而负数时为合法,例如-2+4 前面补零 程序要能处理表达式中间出现的空格(输入表达式中存在空格为合法情况) (后面是运算符 + / * 没数字! )前面是运算符 + - * / 没数字! -) (1 -6)-(-1+2) 010 0 开头的数字 4-

-(9-1) 允许 (9-1)- 不允许 +9+1 不允许 -9+1 允许

Submitted by anonymous - 4 years ago