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PHP Numbers

A number in PHP is a value for counting and maths, written without quotes. An integer is a whole number, and a float is a number with a decimal point.

Three checks, all true

<?php
var_dump(is_int(42));
var_dump(is_float(3.5));
var_dump(is_numeric("42"));

Division can give an integer

The second division has a whole result, so its type is int instead of float.

<?php
var_dump(7 / 2);
var_dump(6 / 2);

echo hides the full float

The two tools disagree, and the var_dump line shows the value PHP actually stored.

<?php
echo 0.1 + 0.2, "\n";
var_dump(0.1 + 0.2);

Remainders with the % operator

The % operator gives the remainder left after whole division.

<?php
echo 7 % 2, "\n";
echo -7 % 2, "\n";

Example

<?php
$total = 25;
$people = 2;
$share = $total / $people;
echo $share, "\n";
echo $total % $people, "\n";

Key points

  • Number values take part in arithmetic directly, with no quotes around them.
  • Use is_int to check whether a value is an integer.
  • Use is_float to check whether a value is a float.
  • Use is_numeric to check whether a value is a number or numeric text.
  • Division gives an integer when the result is whole, and a float when it is not.
  • Floats are stored approximately, so a sum can carry a tiny hidden error.
  • echo rounds a float for display, and var_dump shows the stored value in full.

In this example, a bill of 25 is split between 2 people. Division gives each share as the float 12.5. The % operator gives 1, the amount left over after a whole split.

Note

The sign of a remainder follows the first number, so -7 % 2 gives -1.

Try it Yourself

Edit the code, then press Run.

Running is simulated · Programiz PHP Compiler

Exercise

What does var_dump(6 / 2); print?