let regexp = "/ ^ [0-9] * $/";
something like this: this is a string with regular expressions in it.
so how do you tell if the content of a string is a legal regular expression?
let regexp = "/ ^ [0-9] * $/";
something like this: this is a string with regular expressions in it.
so how do you tell if the content of a string is a legal regular expression?
regular judgment
or try it out
var isreg;
try {
isreg=eval (regexp) instanceof RegExp
} catch (e) {
isreg=false
}
you can tell whether the string is regular
, but you can't tell if the rule is correct.
the demand itself is explosive. Use regularity to judge whether it is regular or not.
I really won't leave an imprint to watch the bosses play
write a simple:
beginning match begins with / matches ^ with or without. The
ending matches a free combination that ends with the ending symbol $with or without collocation / re-collocation igm.
(it's too long. I'll ignore the m first.)
the middle match really doesn't write any characters
/^\/\^?.*(\$?[\/|\/g|\/gi|\/i|\/ig])$/.test("/^sdk332$/ig")
this is still an excellent combination that is illegal and cannot be judged.
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