JavaScript strspn

Finds length of initial segment consisting entirely of characters found in mask. If start or/and length is provided works like strspn(substr($s,$start,$len),$good_chars)

function strspn (str1, str2, start, lgth) {
    // Finds length of initial segment consisting entirely of characters found in mask. If start or/and length is provided works like strspn(substr($s,$start,$len),$good_chars)  
    // 
    // version: 1008.1718
    // discuss at: http://phpjs.org/functions/strspn    // +   original by: Valentina De Rosa
    // +   improved by: Brett Zamir (http://brett-zamir.me)
    // *     example 1: strspn('42 is the answer, what is the question ...', '1234567890');
    // *     returns 1: 2
    // *     example 2: strspn('foo', 'o', 1, 2);    // *     returns 2: 2
    var found;
    var stri;
    var strj;
    var j = 0;    var i = 0;
 
    start = start ? (start < 0 ? (str1.length+start) : start) : 0;
    lgth = lgth ? ((lgth < 0) ? (str1.length+lgth-start) : lgth) : str1.length-start;
    str1 = str1.substr(start, lgth); 
    for (i = 0; i < str1.length; i++){
        found = 0;
        stri  = str1.substring(i,i+1);
        for (j = 0; j <= str2.length; j++) {            strj = str2.substring(j,j+1);
            if (stri == strj) {
                found = 1;
                break;
            }        }
        if (found != 1) {
            return i;
        }
    } 
    return i;
}

external links: original PHP docs | raw js source

Examples

» Example 1

Running

1	strspn('42 is the answer, what is the question ...', '1234567890');

Should return

» Example 2

Running

1	strspn('foo', 'o', 1, 2);

Should return

Dependencies

No dependencies, you can use this function standalone.

Open syntax issues

php.js uses JsLint to help us keep our code consistent and prevent some common bugs.

Eventually we want all code to pass or at least take into consideration most fixes suggested by JsLint, following this JsLint configuration we’ve decided on.

Authors

Thanks to the following developers, you get to have strspn goodness in JavaScript.

Valentina De Rosa ( original )
Brett Zamir ( improved )

Comments

Add Comment

Name

Website

Title

Content

Use:

[CODE]
your_stuff('here');
[/CODE]

for proper code formatting
By submitting code here you are allowing us to use it in php.js hence dual licensing it under the MIT and GPL licenses

Kevin van Zonneveld
30 Dec '08

@ Brett Zamir: Good job man, added!

Brett Zamir
18 Dec '08

I think this should add the other two args...

[CODE="Javascript"]

strspn('42 is the answer, what is the question ...', '1234567890');
strspn("foo", "o", 1, 2); // 2

function strspn(str1, str2, start, lgth){
// http://kevin.vanzonneveld.net
// + original by: Valentina De Rosa
// % note 1: Good start, but still missing the 3rd & 4th argument which came to PHP in version 4.3.0
// * example 1: strspn('42 is the answer, what is the question ...', '1234567890');
// * returns 1: 2

var found;
var stri;
var strj;
var j = 0;
var i = 0;

start = start ? (start < 0 ? (str1.length+start) : start) : 0;
lgth = lgth ? ((lgth < 0) ? (str1.length+lgth-start) : lgth) : str1.length-start;
str1 = str1.substr(start, lgth);

for(i = 0; i < str1.length; i++){
found = 0;
stri = str1.substring(i,i+1);
for (j = 0; j <= str2.length; j++) {
strj = str2.substring(j,j+1);
if (stri == strj) {
found = 1;
break;
}
}
if (found != 1) {
return i;
}
}

return i;
}[/CODE]

Contribute a New function