I'm new to JavaScript and not sure why my code isn't working. I'm trying to return true if there are an equal amount of x's and o's, and return false if there are not. My code works for all inputs except "x" and "o". Any help is appreciated!
My code:
function ExOh(str) {
var x = str.match(/[^x$]/gi);
var o = str.match(/[^o$]/gi);
if (x.length == o.length) {
return true;
}
else {
return false;
}
}
Your regexps allow any characters other than x/y and $. You must have meant /x/gi and /o/gi.
function ExOh(str) {
var x = str.match(/x/gi) || "";
var o = str.match(/o/gi) || "";
if (x.length === o.length) {
return true;
}
else {
return false;
}
}
alert(ExOh("zzz"));
alert(ExOh("oozzzxx"));Note that negated character classes like [^x] match all characters other than those inside the square brackets. $ inside them is treated as a literal dollar sign.
Typing a caret after the opening square bracket negates the character class. The result is that the character class matches any character that is not in the character class. Unlike the dot, negated character classes also match (invisible) line break characters. If you don't want a negated character class to match line breaks, you need to include the line break characters in the class.
[^0-9\r\n]matches any character that is not a digit or a line break.
null and the conditional breaks when calling .length on the null value.=== will also check the type and the value, and match result is better checked for null. Actually, "" and [] yield the same result.
You need to set the value to something other than null if the str.match doesn't actually match something. You can't call length on null. Use the or operator to set the value to an empty string in your variable declaration.
function ExOh(str) {
var x = str.match(/[^x$]/gi) || '';
var o = str.match(/[^o$]/gi) || '';
if (x.length == o.length) {
return true;
}
else {
return false;
}
}
I hope this helps
Here's a solution for checking that the number of two characters is the same.
// How many 'x' characters occur in a string?
function numberOf(str, x) {
var matches = str.match(new RegExp(x, 'g'));
return matches ? matches.length : 0;
}
// Create a function to check if the number of x's and o's in
// a string are the same.
function same(x, o) {
return function(str) {
return numberOf(str, x) === numberOf(str, o);
};
}
var isSame = same('x', 'o');
isSame('xxooabc');
Remove ^ and $ from your regex , [^o$] match a single character not o or $. You just need to use /x/ and /o/ and flags ig, i for ignoring case and g for global match.
Typing a caret after the opening square bracket negates the character class. The result is that the character class matches any character that is not in the character class. Unlike the dot, negated character classes also match (invisible) line break characters. If you don't want a negated character class to match line breaks, you need to include the line break characters in the class. [^0-9\r\n] matches any character that is not a digit or a line break. ( Taken from http://www.regular-expressions.info/charclass.html )
Update : Add (!x && !o) and x && o in condition for avoiing error when zero matches are there. (!x && !o) for when both are not present.x && o will help only to check the condition x.length == o.length when both x and o are defined.
var div = document.getElementById('res');
function ExOh(str) {
var x = str.match(/x/gi);
var o = str.match(/o/gi);
if ((!x&&!o) || x && o && x.length == o.length) {
res.innerHTML = 'Same';
return true;
} else {
res.innerHTML = 'Not Same';
return false;
}
}<input type=text oninput="ExOh(this.value)">
<div id=res></div>