Another doubt when using switch

[Robert Scheer]

Hi.

I am trying to use switch this way, without success:

//thedata is a numeric variable
switch (thedata) {
case < 10:
...
case < 20:
...
case <= 30:
...
}

It seems that switch can only test for single string values. Can't I
make this kind of test using switch?

Thanks,
Robert Scheer

[lallous]

Re: Another doubt when using switch

Hello,

You can't use 'switch' like that...you can check for exact values only, as:

switch(value)
{
case 6:
case 7:
case 8:
// do something
break;
case 100:
// do something else...
break;
default:
// default value...
break;
}

If you need to compare for ranges rather than exact values then the 'if/else
if' is what you need:

if (x < 10) { ...... }
else if (x > 30) { .....}
else { .......}

--
Elias
"Robert Scheer" <rbscheer@my-deja.com> wrote in message
news:cfd22ab6.0 401160650.4defb 9e9@posting.goo gle.com...[color=blue]
> Hi.
>
> I am trying to use switch this way, without success:
>
> //thedata is a numeric variable
> switch (thedata) {
> case < 10:
> ...
> case < 20:
> ...
> case <= 30:
> ...
> }
>
> It seems that switch can only test for single string values. Can't I
> make this kind of test using switch?
>
> Thanks,
> Robert Scheer[/color]

[Douglas Crockford]

Re: Another doubt when using switch

> I am trying to use switch this way, without success:[color=blue]
>
> //thedata is a numeric variable
> switch (thedata) {
> case < 10:
> ...
> case < 20:
> ...
> case <= 30:
> ...
> }
>
> It seems that switch can only test for single string values. Can't I
> make this kind of test using switch?[/color]

Buy a book. You can't expect to program in total ignorance. Fortify yourself
with specific knowledge.

In this case, use an if statement.

if (thedata < 10) {
...
} else if (thedata < 20) {
...
} else if (thedata <= 30) {
....
}

http://www.crockford.com/javascript/javascript.html

[Michael Winter]

Re: Another doubt when using switch

On Fri, 16 Jan 2004 07:42:39 -0800, Douglas Crockford <nospam@covad.n et>
wrote:
[color=blue]
> Buy a book. You can't expect to program in total ignorance. Fortify
> yourself with specific knowledge.[/color]

Even use of the JavaScript language reference would do...

Mike

http://devedge.netscape.com/central/javascript/

--
Michael Winter
M.Winter@blueyo nder.co.invalid (replace ".invalid" with ".uk" to reply)

[Dr John Stockton]

Re: Another doubt when using switch

JRS: In article <bu8v0h$f4s0h$1 @ID-161723.news.uni-berlin.de>, seen in
news:comp.lang. javascript, lallous <lallous@lgwm.o rg> posted at Fri, 16
Jan 2004 17:05:59 :-[color=blue]
>"Robert Scheer" <rbscheer@my-deja.com> wrote in message
>news:cfd22ab6. 0401160650.4def b9e9@posting.go ogle.com...[/color]
[color=blue][color=green]
>> I am trying to use switch this way, without success:
>>
>> //thedata is a numeric variable
>> switch (thedata) {
>> case < 10:
>> ...
>> case < 20:
>> ...
>> case <= 30:
>> ...
>> }
>>
>> It seems that switch can only test for single string values. Can't I
>> make this kind of test using switch?[/color][/color]

You can : see below previous response.


Responses should go after trimmed quotes, as per Wednesday FAQ.
[color=blue]
>You can't use 'switch' like that...you can check for exact values only, as:[/color]

Well, yes and no.

[color=blue]
>If you need to compare for ranges rather than exact values then the 'if/else
>if' is what you need:
>
>if (x < 10) { ...... }
>else if (x > 30) { .....}
>else { .......}[/color]

No. It can be used, but it is not needed.

var X = 265 // the variable
switch(true) {
case X<10 : alert('<10') ; break
case X<20 : alert('<20') ; break
case X<30 : alert('<30') ; break
default : alert('big') }


A post here or elsewhere a few days/weeks ago provided a clue from which
the above is derived. The code appears to be about as long as that with
nested IF; appears legal; can easily be laid out readably; works (at
least in eval in MSIE4); and ISTM that it should be of similar speed.
Advantage: case & break fulfil the role of brackets; more typing, but
easier to pair them up correctly.

To confuse readers : change true to false and reverse the relational
operators ( < to >= ).

--
© John Stockton, Surrey, UK. ?@merlyn.demon. co.uk Turnpike v4.00 IE 4 ©
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