Table of Contents
JavaScript String Operation
A JavaScript String is zero or more characters written within quotes. We can perform following operations on string:
| Operation | Description | Example |
| String Length | We can get length of any string stored in a variable. Syntax: var.length Here, var can be any variable. | var txt = “Gargi”; var sln = txt.length; Output: 5 |
| Finding a String in a String | We can get index (position) of a text in a string. Syntax: indexOf(): Returns first occurrence of the text lastIndexOf():Returns last occurrence of the text | var str = “You will locate me!”; var pos = str.indexOf(“locate“); Output: 9 |
| Slice (start, end) | It extracts a part of a string and returns the extracted part in a new string. It takes two parameters: the starting position and the end position [excluding the end position value] | var str = “I am Rudra!”; var res = str.slice(5, 10); Output: Rudra |
| Substring (start, end) | It is similar to slice(), but it cannot accept negative indexes unlike slice operation. | var str = “I am Rudra!”; var res = str. substring (5, 10); Output: Rudra |
| Substr (start, length) | It is similar to slice(). Here, the second parameter is the length of the text to be extracted. | var str = “I am Rudra!”; var res = str. substr(5, 10); Output: Rudra! |
| Replace () | It replaces a specified value with another value in a string. It is case sensitive and replaces only the first finding. It doesn’t change the original but returns the change into a new variable. | var str = “I am German”; var n = str.replace(“German”, “Indian”); Output: I am Indian |
| Converting Case | To convert a case, we can use the following: 1. toUpperCase() 2. toLowerCase() | var text = “Hello World!”; var uText = text.toUpperCase(); var ltext = text.toLowerCase(); |
| Concat () | It joins two or more strings together. | var text1 = “Hello”; var text2 = “India”; var text3 = text1.concat(” “, text2); |
| Trim () | It removes whitespaces from both side of a given string. | var str = ” Hello India “; alert(str.trim()); |
| Split () | It splits a string based on a condition mentioned within the brackets. | var txt = “a,b,c,d,e”; txt.split(“,”); // Split on commas txt.split(” “); // Split on spaces txt.split(“|”);// Split on pipe txt.split(“”);// Split in characters |
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