admin管理员组

文章数量:1125974

I have a string, and I need to get its first character.

var x = 'somestring';
alert(x[0]); //in ie7 returns undefined

I have a string, and I need to get its first character.

var x = 'somestring';
alert(x[0]); //in ie7 returns undefined

How can I fix my code?

• javascript

Share Improve this question Follow edited Mar 20, 2021 at 7:12 Penny Liu 17.3k55 gold badges8686 silver badges108108 bronze badges asked Aug 6, 2010 at 19:35 SimonSimon 23.1k3636 gold badges9393 silver badges122122 bronze badges 1

• 8 just be careful - you might not have a character there to extract! – corsiKa Commented Aug 6, 2010 at 19:43

Add a comment  | 

22 Answers 22

Sorted by: Reset to default 1313

charAt can give wrong results for Unicode. Use Array.from:

Array.from('some string')[0];

In JavaScript you can do this:

const x = 'some string';
console.log(x.substring(0, 1));

You can use any of these.

There is a little difference between all of these So be careful while using it in conditional statement.

var string = "hello world";
console.log(string.slice(0,1));     //o/p:- h
console.log(string.charAt(0));      //o/p:- h
console.log(string.substring(0,1)); //o/p:- h
console.log(string.substr(0,1));    //o/p:- h
console.log(string[0]);             //o/p:- h
console.log(string.at(0));          //o/p:- h


var string = "";
console.log(string.slice(0,1));     //o/p:- (an empty string)
console.log(string.charAt(0));      //o/p:- (an empty string)
console.log(string.substring(0,1)); //o/p:- (an empty string)
console.log(string.substr(0,1));    //o/p:- (an empty string)
console.log(string[0]);             //o/p:- undefined
console.log(string.at(0));          //o/p:- undefined

Example of all method

First : string.charAt(index)

Return the caract at the index index

var str = "Stack overflow";

console.log(str.charAt(0));

Second : string.substring(start,length);

Return the substring in the string who start at the index start and stop after the length length

Here you only want the first caract so : start = 0 and length = 1

var str = "Stack overflow";

console.log(str.substring(0,1));

Alternative : string[index]

A string is an array of caract. So you can get the first caract like the first cell of an array.

Return the caract at the index index of the string

var str = "Stack overflow";

console.log(str[0]);

const x = 'some string';
console.log(x.substring(0, 1));

var x = "somestring"
alert(x.charAt(0));

The charAt() method allows you to specify the position of the character you want.

What you were trying to do is get the character at the position of an array "x", which is not defined as X is not an array.

You can even use slice to cut-off all other characters:

x.slice(0, 1);

var str="stack overflow";

firstChar  = str.charAt(0);

secondChar = str.charAt(1);

Tested in IE6+, FF, Chrome, safari.

Try this as well:

x.substr(0, 1);

Looks like I am late to the party, but try the below solution which I personally found the best solution:

var x = "testing sub string"
alert(x[0]);
alert(x[1]);

Output should show alert with below values: "t" "e"

You can use any of the following :

let userEmail = "email";
console.log(userEmail[0]); // e
console.log(userEmail.charAt(0)); // e
console.log(userEmail.slice(0, 1)); // e
console.log(userEmail.substring(0, 1)); // e
console.log(userEmail.substr(0, 1)); // e
console.log(userEmail.split("", 1).toString()); // e
console.log(userEmail.match(/./)[0]); // e

x.substring(0,1)

Details

substring(start, end) extracts the characters from a string, between the 2 indices "start" and "end", not including "end" itself.

Special notes

• If "start" is greater than "end", this method will swap the two arguments, meaning str.substring(1, 4) == str.substring(4, 1).
• If either "start" or "end" is less than 0, it is treated as if it were 0.

you can use in this way:

'Hello Mr Been'.split(' ').map( item => item.toUpperCase().substring(0, 1)).join(' ');

It's been 12 years and just one dev mentioned regexp, but it's a simpler way:

const str = 'string';

str.match(/\w/); // >> s

It will return the first character-class-word from the given string.

in Nodejs you can use Buffer :

let str = "hello world"
let buffer = Buffer.alloc(2, str) // replace 2 by 1 for the first char
console.log(buffer.toString('utf-8')) // display he
console.log(buffer.toString('utf-8').length) // display 2

charAt() do not work if it has a parent prop
ex parent.child.chartAt(0)
use parent.child.slice(0, 1)

Since every string is an array, probably the most succinct solution is by using the new spread operator:

const x = 'somestring'
const [head, ...tail] = x
console.log(head) // 's'

bonus is you can now access the total string but the first character using join('') on tail:

console.log(tail.join('')) // 'omestring'

It's been 10 years yet no answer mentioned RegExp.

var x = 'somestring';
console.log(x.match(/./)[0]);

For any string str = "Hello World"

str.split(' ').map( item => item.toUpperCase().substring(0, 1)).join(' ');

Output: H W

There are many ways to find the string first character in Javascript. I think the easiest way to find is the string.charAt() method. This method takes an index number as a parameter and returns the index value. If you didn't give any parameter by default its returns the first character of the string.

 const str = "Bangladesh";
 const firstCharacter = str.charAt(0);
 const secondCharacter = str.charAt(1);
 console.log(firstCharacter)
 console.log(secondCharacter)

in JQuery you can use: in class for Select Option:

$('.className').each(function(){
    className.push($("option:selected",this).val().substr(1));
});

in class for text Value:

$('.className').each(function(){
    className.push($(this).val().substr(1));
});

in ID for text Value:

$("#id").val().substr(1)

You can use as well:

var x = "somestring";

console.log(x.split("")[0]); // output "s"

This should work with older browsers.

本文标签： javascriptHow to get first character of stringStack Overflow