Published May 4, 2022Updated Jul 17, 2023
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The substr() function returns a portion of a string specified by parameters for offset and length.


substr($string, $offset, $length)

The substr() function takes three parameters:

  • $string: a required string from which a portion will be returned.

  • $offset: a required int that specifies the start of the substring in the following manner:

    • Positive or zero values specify the zero-based character position from the start of the string.
    • Negative values indicate the character position from the end of the string.
    • A value greater than the length of $string will return an empty string.
  • $length: an optional int that specifies the number of characters to return in the following manner:

    • Positive values specify to return that number of characters, or characters up to the end of $string if fewer than $length characters are left after $offset is determined.
    • A null or omitted value will return characters from $offset until the end of $string.
    • Negative values will return characters from $offset until $length characters from the end of $string.
    • A value of zero, or a negative value that specifies a position before $offset, will return an empty string.


The following example uses the substr() function to return a substring from the given string. Then the echo command prints this new string to the console:

echo (substr("I am learning PHP.", 14, 3));

The example will result in the following output:


Codebyte Example

The following example gives three examples of the substr() function operating on the same string.

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