JavaScript offers many ways to check if a string contains a substring. Learn the canonical way, and also find out all the options you have, using plain JavaScript
Read this article to learn more about the String.includes() method in JavaScript. String.indexOf() Method The String.indexOf() method returns the index of the first occurrence of the substring. If the string does not contain the given substring, it returns -1. The indexOf() method is ca...
const str = 'React is a popular JavaScript library.' const substr = 'React' if (str.includes(substr)) { console.log(`String contains "${substr}"`) } else { console.log(`String does not contain "${substr}"`) } // String contains "React" The String.includes() method takes two ...
If the string does not contain the substring then it will return null. We will take an example to understand it. var actualstring = "Javascript match method", var substringToCheck = "match"; actualstring.match("match"); //["match", index: 11, input: "Javascript match method", ...
To check if a string does not contain letters, use the JavaScript methods, such as the test() method or the match() method.
For first case: We are checking string (substring)"How"in the stringstr, the condition will be true because stringstrcontains"How"but in other (second) case we are cheking"Who"which is not exists in stringstri.e. stringstrdoes not contain the substring “Who”. Thus, condition will be...
Use the `RegExp.test()` method to check if a string contains only letters and numbers in JavaScript.
Disable HTML button after clicking on it in JavaScript If the returned value byindexOf()method is greater than -1, it means the string contains the specific word. On the other hand, if the returned value is -1 then the string doesn’t contain the word. ...
To check if a string contains only digits in Java, you can use the matches() method of the String class in combination with the regular expression "\\d+".
String and Integers in Java are often used for storing data, but sometimes we might want to check if one data type contains elements compatible with another data type or not.As we know that a String can contain alphabets, symbols, and numbers, it is useful to determine the type of data ...