将正则表达式与数值和小数匹配 [英] Match regex with numeric value and decimal
问题描述
我需要将正则表达式与带小数的数字值匹配.目前我有/^-?[0-9]\d*(.\d+)/但它不占 .00我该如何解决这个问题
I need to match regex to value that is numeric with decimal. Currently I have /^-?[0-9]\d*(.\d+)/ but it does not account for .00 How would I fix that
当前有效:
1
1.0
1.33
.00
当前无效:
Alpha Character
推荐答案
您需要处理两种可能性(没有小数部分的数字和没有整数部分的数字):
You need to handle the two possibilities (numbers without a decimal part and numbers without an integer part):
/\A-?(?:\d+(?:\.\d*)?|\.\d+)\z/
#^ ^ ^ ^^ ^---- end of the string
#| | | |'---- without integer part
#| | | '---- OR
#| | '---- with an optional decimal part
#| '---- non-capturing group
#'---- start of the string
或将所有选项都设为可选并确保至少有一位数字:
or make all optional and ensure there's at least one digit:
/\A-?+(?=.??\d)\d*\.?\d*\z/
# ^ ^ ^ ^---- optional dot
# | | '---- optional char (non-greedy)
# | '---- lookahead assertion: means "this position is followed by"
# '---- optional "-" (possessive)
注意:我使用非贪婪量词 ??
只是因为我相信整数部分的数字更频繁,但这可能是一个错误的假设.在这种情况下,将其更改为贪婪量词 ?
.(无论您对未知字符"使用哪种量词都没有关系,这不会改变结果.)
Note: I used the non-greedy quantifier ??
only because I believe that numbers with integer part are more frequent, but it can be a false assumption. In this case change it to a greedy quantifier ?
. (whatever the kind of quantifier you use for the "unknow char" it doesn't matter, this will not change the result.)
这篇关于将正则表达式与数值和小数匹配的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!