How do you find the index of a particular character in a string in javascript?
ExamplesSearch a string for "welcome": Show
let text = "Hello world, welcome to the universe."; Try it Yourself » Search a string for "Welcome": let text = "Hello world, welcome to the universe."; Try it Yourself » Find the first occurrence of "e": let text = "Hello world, welcome to the universe."; Try it Yourself » Find the first occurrence of "e", starting at position 5: let text = "Hello world, welcome to the universe."; Try it Yourself » Find the first occurrence of "a": let text = "Hello world, welcome to the universe."; Try it Yourself » Definition and UsageThe The The Syntaxstring.indexOf(searchvalue, start) Parameters
Return Value
The Differense BetweenString indexOf() and String search()The The Browser Support
ES1 (JavaScript 1997) is fully supported in all browsers:
The Parameters
Substring to search for, coerced to a string. If the method is called with no arguments, position OptionalThe method returns the index of the first occurrence of the specified substring at a position greater than or equal to
Return valueThe
index of the first occurrence of Return value when using an empty search stringSearching for an empty search string produces strange results. With no second argument, or with a second argument whose value is less than the calling string's length, the return value is the same as the value of the second argument:
However, with a second argument whose value is greater than or equal to the string's length, the return value is the string's length:
In the former instance, the method behaves as if it found an empty string just after the position specified in the second argument. In the latter instance, the method behaves as if it found an empty string at the end of the calling string. DescriptionStrings are zero-indexed: The index of a string's first character is
The
Checking occurrencesWhen checking if a specific substring occurs within a string, the correct way to check is test whether the return value is
ExamplesUsing indexOf()
The following example uses
indexOf() and case-sensitivityThe following example defines two string variables. The variables contain the same string, except that the second string contains uppercase letters. The first
Using indexOf() to count occurrences of a letter in a string The following
example sets
Specifications
Browser compatibilityBCD tables only load in the browser See alsoHow do you find the index of a certain character in a string?The indexOf() method returns the position of the first occurrence of specified character(s) in a string. Tip: Use the lastIndexOf method to return the position of the last occurrence of specified character(s) in a string.
How do I see all indexes in a string?To get all indexes of a specific character in a string:
Create an empty array that will store the indexes. Use a for loop and loop from 0 up to the string's length. For each iteration of the loop, check if the character at that index is equal to the specific character.
How do you find the last index of a character in a string in JavaScript?The lastIndexOf() method returns the index (position) of the last occurrence of a specified value in a string. The lastIndexOf() method searches the string from the end to the beginning. The lastIndexOf() method returns the index from the beginning (position 0).
What does indexOf do in JavaScript?indexOf() The indexOf() method, given one argument: a substring to search for, searches the entire calling string, and returns the index of the first occurrence of the specified substring.
What is the index of the first character in a string?The first character in a string is present at index zero and the last character in a string is present at index length of string-1 .
Can index be used on strings?Strings are ordered sequences of character data, 00:15 and the individual characters of a string can be accessed directly using that numerical index. String indexing in Python is zero-based, so the very first character in the string would have an index of 0 , 00:30 and the next would be 1 , and so on.
|