Preserved Topic: How do I determine the casing of a letter? (Page 1 of 1)

Lets say i wanted to take all of the capital letters of a string and delete them; how would i determine if a letter is a lowercase or an uppercase letter?

You're best bet is probably a regular expressions
say you have a string called "str"

then you need a regular espression to match uppercase letters, this is pretty easy

re = /[A-Z]/g;


then replace anything that matches the regexp.
str.replace(re,"");



.:[ Never resist a perfect moment ]:.

it's for perl, but I think the regexp's work the same..


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usually to do that from the very low level you have to check each character's ascii code range,
for example the upper case 'A' has the ascii code of: 65 (try to press ALT+65 on your keyboard) now add 25 to 65 you end up having the ascii code of the 'Z' .

the lowercase 'a' has ascii code of 97 (97-65 = 32) therefore you can convert from lowercase to uppercase by adding or substracting 32 from the characters ascii code.

hope that helps.

as for js implementation, refer to String.charCodeAt(index) and .fromCharCode()


Elias

function reversecaps() {



invcasing=document.f.source.value

var outcase=""

for (var letter=0;letter<invcasing.length;letter++) {

str=invcasing.charCharCodeAt(invcasing[letter])

if (str>96 && str<122) { newoutcase = str.fromCharCode(str-65); } else {newoutcase = str.fromCharCode(str+65);}

outcase=outcase+newoutcase

}

document.f.source.value=outcase }

doesn't work. can't figure it out.

You have a few errors in your code. Here's the fixed version:

function reversecaps()
{
invcasing=document.f.source.value
var outcase=""
for (var letter=0;letter<invcasing.length;letter++) {
&nbsp;&nbsp;&nbsp;&nbsp;str=invcasing.charCodeAt(letter)
&nbsp;&nbsp;&nbsp;&nbsp;if (str>96 && str<123) { newoutcase = String.fromCharCode(str-32); } else { newoutcase = String.fromCharCode(str+32); }
&nbsp;&nbsp;&nbsp;&nbsp;alert(String.fromCharCode(str)+" "+newoutcase);
&nbsp;&nbsp;&nbsp;&nbsp;outcase=outcase+newoutcase
}
document.f.source.value=outcase
}

pretty elegant solution, lallous..


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ICQ: 67751342

I havent read the other posts but:
if(thestring.toUppercase()==thestring) alert('the string is upper case !');

Im not sure on the spelling of toUppercase I think thats it.

to lets say count how many are upper case:
for(i=0;i<thestring.length;i++) { if(thestring[i].toUppercase()==thestring[i]) amountuppercse++; }
that should work, I cant remember if JS saves strings as arrays, you might need theString.charAt(i), I think, its been a while since I'vev used JS to mess with strings.

....

just looking at Lallous' idea, its seems a little nicer and probably less work for the CPU.