i'm looking for a regex expression or javascript which alerts me when a number is NOT between 48-47 or NOT between 96-105 or IS NOT 110 OR 190 OR 8 OR 13.
thanks for all the help friends !!
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12I would strongly urge you to accept an answer to some of your other questions.matchew– matchew2011-06-16 21:31:54 +00:00Commented Jun 16, 2011 at 21:31
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6Why would you do this with a regex instead of doing simpler (and faster!) numeric comparisons?Pointy– Pointy2011-06-16 21:33:54 +00:00Commented Jun 16, 2011 at 21:33
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4Regexps are not really meant for this..erlando– erlando2011-06-16 21:34:31 +00:00Commented Jun 16, 2011 at 21:34
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3 Answers
Regex is not appropriate for such specific numeric checks. Just do a few if statements to compare the value you're working with to the specific values and ranges you want to exclude.
var number = 19;
alert('Number is'+(numberIsValid(number) ? 'valid' : 'not valid'));
function numberIsValid(number) {
// test for numeric argument
if ((number - 0) != number)
return false;
// test for specific exclusions
if (number == 110 || number == 190 || number == 8 || number == 13 || number == 48 || number == 47)
return false;
// test for excluded range
if (number >= 96 && number <= 105)
return false;
return true;
}
6 Comments
Eevee
Boo for implicit conversions. Rather use
parseInt(number, 10) and isNaN.
Pointy
@Eevee why? "parseInt()" is actually kind-of a pain, because it'll return a valid number from the string "12hello there". Implicit conversion will not.
Chris Baker
Implicit conversion is more efficient and a much more direct way to test for numeric, there really isn't a compelling reason not to use this pattern. It isn't considered part of "best practice", IMO, similar to how array literals are more efficient even though there is a more formal way to instantiate an array.
Eevee
@Pointy: Relying on weak typing behavior is often wacky and subtle, so I try to avoid it. But that's a good point. Could use
Number(), which ought to work the same as the implicit conversion, though it doesn't seem to be a popular approach.Chris Baker
Javascript is a weakly typed language. There's no sense in avoiding that fact because it seems "wacky"; that's the way it is, and that's the way it will stay, so there's no danger in using that to your advantage when you can. :)
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I agree with Chris's response above, if you want to see what it would look like, it is kind of a mess. I wouldn't really recommend you use this.
Just to rephrase: Number may not be 8,13,47,48,96-105,110
var num = 10;
if (! /^(8|13|47|48|9[6-9]|10[0-5]|110)$/.test(num)) {
alert(num);
}
1 Comment
Chris Baker
Ugh. +1 for cobbling it together... I wasn't even going to try.
