Strings in JavaScript

Link for all dot net and sql server video tutorial playlists

Link for slides, code samples and text version of the video

In this video we will discuss different functions that are available to manipulate string in JavaScript.

A string is any text inside quotes. You can use either single or double quotes.
var string1 = “string in double quotes”
var string2 = ‘string in single quotes’

Concatenating strings : There are 2 options to concatenate strings in JavaScript. You could either use + operator or concat() method

Example : Concatenating strings using + operator
var string1 = “Hello”
var string2 = “JavaScript”
var result = string1 + ” ” + string2;
alert(result);

Output : Hello JavaScript

Example : Concatenating strings using concat() method
var string1 = “Hello”
var string2 = “JavaScript”
var result = string1.concat(” “, string2);
alert(result);

Output : Hello JavaScript

If you want single quotes inside a string, there are 2 options
Option 1 : Place your entire string in double quotes, and use single quotes inside the string wherever you need them.

Example :
var myString = “Welcome to ‘JavaScript’ Training”;
alert(myString);

Output : Welcome to ‘JavaScript’ Training

Option 2 : If you prefer to place your entire string in single quotes, then use escape sequence character with a single quote inside the string.

Example :
var myString = ‘Welcome to ‘JavaScript’ Training’;
alert(myString);

Output : Welcome to ‘JavaScript’ Training

Please Note : You can use the above 2 ways if you need double quotes inside a string

Converting a string to uppercase : Use toUpperCase() method

Example :
var upperCaseString = “JavaScript”;
alert(upperCaseString.toUpperCase());

Output : JAVASCRIPT

Converting a string to lowercase : Use toLowerCase() method

Example :
var lowerCaseString = “JavaScript”;
alert(lowerCaseString.toLowerCase());

Output : javascript

Length of string javascript : Use length property

Example : alert(“JavaScript”.length);

Output : 10

Example :
var myString = “Hello JavaScript”;
alert(myString.length);

Output : 16

Remove whitespace from both ends of a string : Use trim() method

Example :
var string1 = ” AB “;
var string2 = ” CD “;
var result = string1.trim() + string2.trim();
alert(result);

Output : ABCD

Replacing strings in javascript : Use replace() method. This method searches a given string for a specified value or a regular expression, replaces the specified values with the replacement values and returns a new string. This method does not change the original string.

Example : Replaces JavaScript with World
var myString = “Hello JavaScript”;
var result = myString.replace(“JavaScript”, “World”);
alert(result);

Output : Hello World

Example : Perform a case-sensitive global replacement. In this example, we are using a regular expression between the 2 forward slashes(//). The letter g after the forward slash specifies a global replacement. The match here is case sensitive. This means Blue(with capital B) is not replaced with green.

var myString = “A Blue bottle with a blue liquid is on a blue table”;
var result = myString.replace(/blue/g, “green”);
alert(result);

Output : A Blue bottle with a green liquid is on a green table

Example : Perform a case-insensitive global replacement. The letters gi after the forward slash indicates to do global case-insensitive replacement. Notice that the word Blue(with capital B) is also replaced with green.

Nguồn: https://vinhtrinh.com.vn

Xem thêm bài viết khác: https://vinhtrinh.com.vn/cong-nghe/