Thủ Thuật về How to extract characters from a string in javascript Mới Nhất
Hoàng Quang Hưng đang tìm kiếm từ khóa How to extract characters from a string in javascript được Update vào lúc : 2022-10-27 05:16:08 . Với phương châm chia sẻ Kinh Nghiệm về trong nội dung bài viết một cách Chi Tiết 2022. Nếu sau khi tham khảo nội dung bài viết vẫn ko hiểu thì hoàn toàn có thể lại Comments ở cuối bài để Admin lý giải và hướng dẫn lại nha.Almost in every IT job interview, the interviewers will surely bring out the topics related to string, and ask the interviewee to perform some operation on a string. To extract a substring from a string is one of those questions. So, in this article, we shall go through some methods to extract a substring from a string in JavaScript language.
Nội dung chính Show- What is a string?Using substring() to extract a substringExtract a substring using the split() function1. String slice() Method2. String substring() Method11 Amazing New JavaScript Features in ES13How do I extract something from a string in JavaScript?How do you find a specific character in a string JavaScript?Can you slice a string in JavaScript?How do substring () and substr () differ?
What is a string?
In programming, a string is a data type like integers and float that is formed using characters data type in combination. It is usually plain text that resides between two double quotations. For example, "I like JavaScript programming".
Using substring() to extract a substring
Substring() is a JavaScript function that extracts a portion of some entered string.
Here are some examples of using substring() to extract a substring using the substring() function.
Code:
The substring() extracts a part of a string
Output:
Run Code
Explaining the above program:
Here, The variable text stores the string, and the result variable will store the extracted substring.The id attribute used is for defining the HTML element.In the line, let result = text.substring(1, 4), the function substring() gets called, and passing parameters (1,4) will separate the characters from position 1 to 4 and store it in the result variable.Lastly, return the extracted substring stored in the result using the innerHTML method.Extract a substring using the split() function
Similar to the substring(), the split() function also returns a part of a string. The string gets divided and the separation depends on the parameter we pass to the split() function. The split() function will split every character in the string if ("") is the parameter, and it will separate the words if (" ") is the parameter.
Code:
Program to extract a substring from a string
Extract the desired word from a string
The second word is:
Output:
Run Code
Working of the program:
Here, the variable text stores the string, and the id attribute will define the HTML element.In the line, const myArray = text.split(" "), the split() function will separate the string stored in the variable text. Every word gets split and stored in the myArray array.Lastly, it will return the substring from the array using the innerHTML method.Conclusion:
This article was about the methods for extracting a substring from a string. Handling strings and substrings are essential for everyone to create large applications. There are several methods and inbuilt functions in JavaScript for that purpose. There are two functions described in the above article for extracting a substring from a string. They are, substring(), split().
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1. String slice() Method
To get the first N characters of a string in JavaScript, call the slice() method on the string, passing 0 as the first argument and N as the second. For example, str.slice(0, 2) returns a new string containing the first 2 characters of str.
const str="Coding Beauty"; const first2 = str.slice(0, 2); console.log(first2); // Co const first6 = str.slice(0, 6); console.log(first6); // Coding const first8 = str.slice(0, 8); console.log(first8); // Coding BThe String slice() method extracts the part of a string between the start and end indexes, which are specified by the first and second arguments respectively. The substring between the indexes 0 and N is a substring containing only the first N string characters.
NoteStrings in JavaScript are immutable, and the slice() method returns a new string without modifying the original:
const str="Coding Beauty"; const first2 = str.slice(0, 2); console.log(first2); // Co // Original not modified console.log(str); // Coding Beauty2. String substring() Method
To get the first N characters of a string, we can also call the substring() method on the string, passing 0 and N as the first and second arguments respectively. For example, str.substring(0, 3) returns a new string containing the first 3 characters of str.
const str="Coding Beauty"; const first3 = str.substring(0, 3); console.log(first3); // Cod const first5 = str.substring(0, 5); console.log(first5); // Codin const first11 = str.substring(0, 11); console.log(first11); // Coding BeauLike slice(), substring() returns the part of a string between the start and end indexes, which are specified by the first and second arguments respectively.
Notesubstring() returns a new string without modifying the original:
const str="Coding Beauty"; const first3 = str.substring(0, 3); console.log(first3); // Cod // Original not modified console.log(str); // Coding Beauty TipThe slice() and substring() methods work similarly for our scenario, but this isn’t always the case. Here’s one difference between them: substring() swaps its arguments if the first is greater than the second, but slice() returns an empty string (''):
const str="Coding Beauty"; const substr1 = str.substring(2, 0); const substr2 = str.slice(2, 0); // Equivalent to str.substring(0, 2) console.log(substr1); // Co console.log(substr2); // '' (empty string)11 Amazing New JavaScript Features in ES13
This guide will bring you up to speed with all the latest features added in ECMAScript 13. These powerful new features will modernize your JavaScript with shorter and more
expressive code.
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Ayibatari Ibaba is a software developer with years of experience building websites and apps. He has written extensively on a wide range of programming topics and has created dozens of apps and open-source libraries.
How do I extract something from a string in JavaScript?
The substr() method extracts a part of a string. The substr() method begins a specified position, and returns a specified number of characters. The substr() method does not change the original string. To extract characters from the end of the string, use a negative start position.How do you find a specific character in a string JavaScript?
The indexOf() method returns the position of the first occurrence of a value in a string. The indexOf() method returns -1 if the value is not found. The indexOf() method is case sensitive.Can you slice a string in JavaScript?
String.prototype.slice() The slice() method extracts a section of a string and returns it as a new string, without modifying the original string.How do substring () and substr () differ?
The difference between substring() and substr() The two parameters of substr() are start and length , while for substring() , they are start and end . substr() 's start index will wrap to the end of the string if it is negative, while substring() will clamp it to 0 . Tải thêm tài liệu liên quan đến nội dung bài viết How to extract characters from a string in javascript