Checking whether a string is all digits

[Christopher Benson-Manica]

I'm trying to check whether a string is all digits. This part is
easy:

function allDigits( str ) {
var foo=str.split( '' ); // better than charAt()?
for( var idx=0; idx < foo.length; idx++ ) {
if( !isDigit(foo[idx]) ) {
return false;
}
}
return true;
}

I'm not sure about how to implement isDigit(). Is this the best way?

function isDigit( s ) {
if( s.length > 1 ) {
return false;
}
var nums='123456789 0';
return nums.indexOf(s) != -1;
}

--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cybers pace.org | don't, I need to know. Flames welcome.

[drWot]

String.prototyp e.isdigits=func tion(){
return (/\D/.test(this)==fa lse);
}

This returns true if there are no non-digits in the string.
Since it is a prototype method, call it for a string str like this:

if(str.isdigits ()){do something}
else {do something else}

[Lasse Reichstein Nielsen]

Christopher Benson-Manica <at***@nospam.c yberspace.org> writes:

I'm trying to check whether a string is all digits.

For that, regular expressions is the simplest way, by some orders
of magnitude :)

function allDigits(str) {
return /^\d*$/.test(str); // consists of only digits from start to end
}

or even:

function allDigits(str) {
return !/\D/.test(str); // doesn't contain non-digit
}

This accepts the empty string, which is, technically, all digits
(there is nothing but digits). If you want only non-empty strings,
change it to:

function allDigits(str) {
return /^\d+$/.test(str);
}
Good luck.
/L
--
Lasse Reichstein Nielsen - lr*@hotpop.com
DHTML Death Colors: <URL:http://www.infimum.dk/HTML/rasterTriangleD OM.html>
'Faith without judgement merely degrades the spirit divine.'

[Vic Sowers]

"Christophe r Benson-Manica" <at***@nospam.c yberspace.org> wrote in message
news:d8******** **@chessie.cirr .com...

I'm trying to check whether a string is all digits. This part is
easy:

function allDigits( str ) {
var foo=str.split( '' ); // better than charAt()?
for( var idx=0; idx < foo.length; idx++ ) {
if( !isDigit(foo[idx]) ) {
return false;
}
}
return true;
}

I'm not sure about how to implement isDigit(). Is this the best way?

function isDigit( s ) {
if( s.length > 1 ) {
return false;
}
var nums='123456789 0';
return nums.indexOf(s) != -1;
}

--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cybers pace.org | don't, I need to know. Flames welcome.

allDigits = str.split(/\d/).length==0

[Lasse Reichstein Nielsen]

"Vic Sowers" <Mail@Vic_NOSPA M_Sowers.com> writes:

"Christophe r Benson-Manica" <at***@nospam.c yberspace.org> wrote in message
news:d8******** **@chessie.cirr .com...

I'm trying to check whether a string is all digits.

.... allDigits = str.split(/\d/).length==0

Test your code :)

Either do:

var allDigits = (str.split(/\d/).length == (str.length+1)) ;

or

var allDigits = (str.split(/\D/).length <= 1);

The length of someString.spli t(...) is never 0.
/L
--
Lasse Reichstein Nielsen - lr*@hotpop.com
DHTML Death Colors: <URL:http://www.infimum.dk/HTML/rasterTriangleD OM.html>
'Faith without judgement merely degrades the spirit divine.'

[cosmic fool]

you guys are nerds

[Zif]

cosmic fool wrote:

you guys are nerds

Read the FAQ. Do not top post. Quote what you are replying to.

<URL:http://jibbering.com/faq/#FAQ2_3>

--
Zif

[cosmic fool]

exactly

"Zif" <zi***@hotmail. com> wrote in message
news:Pw******** *********@news. optus.net.au...

cosmic fool wrote:

you guys are nerds

Read the FAQ. Do not top post. Quote what you are replying to.

<URL:http://jibbering.com/faq/#FAQ2_3>

--
Zif

[Vic Sowers]

"Lasse Reichstein Nielsen" <lr*@hotpop.com > wrote in message
news:ek******** **@hotpop.com.. .

"Vic Sowers" <Mail@Vic_NOSPA M_Sowers.com> writes:

"Christophe r Benson-Manica" <at***@nospam.c yberspace.org> wrote in
message
news:d8******** **@chessie.cirr .com...

I'm trying to check whether a string is all digits.

...

allDigits = str.split(/\d/).length==0

Test your code :)

Either do:

var allDigits = (str.split(/\d/).length == (str.length+1)) ;

or

var allDigits = (str.split(/\D/).length <= 1);

The length of someString.spli t(...) is never 0.

Odd... "1234567890".sp lit(/\d/).length is 0 in IE and 11 in Firefox.

[RobG]

Vic Sowers wrote:
[...]

Either do:

var allDigits = (str.split(/\d/).length == (str.length+1)) ;

or

var allDigits = (str.split(/\D/).length <= 1);

The length of someString.spli t(...) is never 0.

Odd... "1234567890".sp lit(/\d/).length is 0 in IE and 11 in Firefox.

You think that's weird? Try this:

alert( "".split(/\d/).length );
alert( "1".split(/\d/).length );
Firefox reports: 1 then 2, but IE reports 1 then 0. Explain that and
keep a straight face.

Using a letters rather than a digits gives exactly the same result.

alert( "".split(/\w/).length );
alert( "a".split(/\w/).length );

Firefox: 1 then 2, IE: 1 then 0.

Here's another:

y = [ ]; alert(y.length) // Both browsers say 0
y = [ ,,, ]; alert(y.length) // Firefox says 3, IE says 4
y = [ ,,,'' ]; alert(y.length) // Firefox says 4, IE says 4

If the last element is undefined, Firefox doesn't add it to the array.

One or the other has got to be in error. Bottom line: be very careful
when building arrays.

--
Rob