Get the first digit of a number in PHP

In this tutorial, we are going to learn about how to get the first digit of a number in PHP with the help of examples.

In PHP, strings are the sequence of characters, where the index of the first character is 0, the second character is 1, third character is 3, last character index is -1 etc.

Negative indexes are used to access the characters from the end of a string in PHP.

Consider, we have a following number:

$pincode=232543;

To get the first digit of a number:

1. Convert the number to a string using the explicit type casting eg: string($pincode).

2. Use the square brackets syntax $string[0] to access the first character of a string.

3. Convert the result back to a number to get the first digit of the number.

Here is an example:

$pincode=232543;
$str = (string)$pincode; # int to string
# accessing the first character then string to int
$result = (int)$str[0];
echo $result;

Output:

2

In the example above, first we converted the number to a string, so we can use the square brackets syntax on it.

You can access the characters of a string, by using the square brackets syntax and specifying an index.

0 is the index of a first character in the string.

Alternatively, we can also use the substr() function in PHP to get the first digit of a number.

The substr() function accepts three arguments, the first one is string, the second is start position, third is length.Then returns the specified part of a string from the start position.

Here is an example:

$pincode=232543;
$str = (string)$pincode;
$result = (int)substr($str, 0, 1);
echo $result;

Output:

2

In the example above, we have passed 0, 1 as second and third arguments to the substr() function. so it begins the string extraction at index 0 and extracts before the index 1.

The substr() function doesn’t mutate the original string, instead of creates a new string with the modified output.