How do I check if string contains substring?
JavascriptJqueryStringSubstringContainsJavascript Problem Overview
I have a shopping cart that displays product options in a dropdown menu and if they select "yes", I want to make some other fields on the page visible.
The problem is that the shopping cart also includes the price modifier in the text, which can be different for each product. The following code works:
$(document).ready(function() {
$('select[id="Engraving"]').change(function() {
var str = $('select[id="Engraving"] option:selected').text();
if (str == "Yes (+ $6.95)") {
$('.engraving').show();
} else {
$('.engraving').hide();
}
});
});
However I would rather use something like this, which doesn't work:
$(document).ready(function() {
$('select[id="Engraving"]').change(function() {
var str = $('select[id="Engraving"] option:selected').text();
if (str *= "Yes") {
$('.engraving').show();
} else {
$('.engraving').hide();
}
});
});
I only want to perform the action if the selected option contains the word "Yes", and would ignore the price modifier.
Javascript Solutions
Solution 1 - Javascript
Like this:
if (str.indexOf("Yes") >= 0)
...or you can use the tilde operator:
if (~str.indexOf("Yes"))
This works because indexOf()
returns -1
if the string wasn't found at all.
Note that this is case-sensitive.
If you want a case-insensitive search, you can write
if (str.toLowerCase().indexOf("yes") >= 0)
Or:
if (/yes/i.test(str))
The latter is a regular expression or regex.
Regex breakdown:
/
indicates this is a regexyes
means that the regex will find those exact characters in that exact order/
ends the regexi
sets the regex as case-insensitive.test(str)
determines if the regular expression matchesstr
To sum it up, it means it will see if it can find the lettersy
,e
, ands
in that exact order, case-insensitively, in the variablestr
Solution 2 - Javascript
You could use search or match for this.
str.search( 'Yes' )
will return the position of the match, or -1 if it isn't found.
Solution 3 - Javascript
It's pretty late to write this answer, but I thought of including it anyhow. String.prototype
now has a method includes
which can check for substring. This method is case sensitive.
var str = 'It was a good date';
console.log(str.includes('good')); // shows true
console.log(str.includes('Good')); // shows false
To check for a substring, the following approach can be taken:
if (mainString.toLowerCase().includes(substringToCheck.toLowerCase())) {
// mainString contains substringToCheck
}
Check out the documentation to know more.
Solution 4 - Javascript
Another way:
var testStr = "This is a test";
if(testStr.contains("test")){
alert("String Found");
}
** Tested on Firefox, Safari 6 and Chrome 36 **
Solution 5 - Javascript
ECMAScript 6 introduces String.prototype.includes
, previously named contains
.
It can be used like this:
'foobar'.includes('foo'); // true
'foobar'.includes('baz'); // false
It also accepts an optional second argument which specifies the position at which to begin searching:
'foobar'.includes('foo', 1); // false
'foobar'.includes('bar', 1); // true
It can be polyfilled to make it work on old browsers.
Solution 6 - Javascript
> The includes() method determines whether one string may be found within another string, returning true or false as appropriate. > >Syntax :-string.includes(searchString[, position]) > >searchString:-A string to be searched for within this string. > >position:-Optional. The position in this string at which to begin searching for searchString; defaults to 0.
string = 'LOL';
console.log(string.includes('lol')); // returns false
console.log(string.includes('LOL')); // returns true
Solution 7 - Javascript
You can use this Polyfill in ie and chrome
if (!('contains' in String.prototype)) {
String.prototype.contains = function (str, startIndex) {
"use strict";
return -1 !== String.prototype.indexOf.call(this, str, startIndex);
};
}
Solution 8 - Javascript
If you are capable of using libraries, you may find that Lo-Dash JS library is quite useful. In this case, go ahead and check _.contains()
(replaced by _.includes()
as of v4).
(Note Lo-Dash convention is naming the library object _. Don't forget to check installation in the same page to set it up for your project.)
_.contains("foo", "oo"); // → true
_.contains("foo", "bar"); // → false
// Equivalent with:
_("foo").contains("oo"); // → true
_("foo").contains("bar"); // → false
In your case, go ahead and use:
_.contains(str, "Yes");
// or:
_(str).contains("Yes");
..whichever one you like better.
Solution 9 - Javascript
I know that best way is str.indexOf(s) !== -1;
http://hayageek.com/javascript-string-contains/
I suggest another way(str.replace(s1, "") !== str
):
var str = "Hello World!", s1 = "ello", s2 = "elloo";
alert(str.replace(s1, "") !== str);
alert(str.replace(s2, "") !== str);
Solution 10 - Javascript
You can also check if the exact word is contained in a string. E.g.:
function containsWord(haystack, needle) {
return (" " + haystack + " ").indexOf(" " + needle + " ") !== -1;
}
Usage:
containsWord("red green blue", "red"); // true
containsWord("red green blue", "green"); // true
containsWord("red green blue", "blue"); // true
containsWord("red green blue", "yellow"); // false
This is how jQuery does its hasClass method.
Solution 11 - Javascript
you can define an extension method and use it later.
String.prototype.contains = function(it)
{
return this.indexOf(it) != -1;
};
so that you can use in your page anywhere like:
var str="hello how are you";
str.contains("are");
which returns true.
Refer below post for more extension helper methods. Javascript helper methods
Solution 12 - Javascript
None of the above worked for me as there were blank spaces but this is what I did
tr = table.getElementsByTagName("tr");
for (i = 0; i < tr.length; i++) {
td = tr[i].getElementsByTagName("td")[0];
bottab.style.display="none";
bottab2.style.display="none";
if (td) {
var getvar=td.outerText.replace(/\s+/, "") ;
if (getvar==filter){
tr[i].style.display = "";
}else{
tr[i].style.display = "none";
}
}
}