JavaScript substr()
Poor Man
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JavaScript substr()#
The substr() method in JavaScript is used to extract a part of a string, starting from a specified position and for a specified length of characters. It can be used to retrieve a substring from the original string.
Syntax:#
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string.substr(start, length)start: Required. The position where to start the extraction from. A positive number represents the index of the character to start from, while a negative number represents the position from the end of the string. For example, -1 represents the last character of the string.length: Optional. The number of characters to extract. If omitted, all characters from the start position to the end of the string will be extracted.
Examples:#
Let's say we have a string "Hello, World!":
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const str = "Hello, World!";To extract the first 5 characters from the string, we can use:
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const substr1 = str.substr(0, 5);The value of substr1 will be "Hello".
To extract the last 6 characters from the string, we can use:
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const substr2 = str.substr(-6);The value of substr2 will be "World!".
Multiple ways to achieve the same result:#
- We can also use the
slice()method to achieve the same result. The syntax is similar tosubstr(), except thatslice()uses the end position instead of the length. - We can also use string indexing to extract substrings. For example,
str[0]will give us the first character of the string, andstr[2]will give us the third character of the string.
Overall, the substr() method is a useful way to extract substrings from a larger string in JavaScript.