# What is the difference between the | and || or operators?

In PHP, the "|" and "||" operators are both bitwise and logical operators. The "|" operator is a bitwise OR operator, and the "||" operator is a logical OR operator.

The difference between these two operators is in the way they evaluate the expressions on either side of them. The bitwise OR operator "|" compares each bit of the first expression to the corresponding bit of the second expression and returns a result in which each bit is set to 1 if either of the corresponding bits is set to 1.

The logical OR operator "||" evaluates the expressions on either side of it and returns a boolean value of true if either of the expressions is true, and false if both expressions are false.

Here is an example to illustrate the difference between these two operators:

``````<?php

\$a = 4; // binary equivalent is 100
\$b = 5; // binary equivalent is 101

\$c = \$a | \$b; // performs a bitwise OR operation, resulting in 101 (decimal 5)
\$d = \$a || \$b; // performs a logical OR operation, resulting in true

echo "a = \$a (binary " . decbin(\$a) . ")\n";
echo "b = \$b (binary " . decbin(\$b) . ")\n";
echo "a | b = \$c (binary " . decbin(\$c) . ")\n";
echo "a || b = " . (\$d ? 'true' : 'false') . "\n";``````

In this example, the variable `\$a` is assigned the decimal value 4, which has a binary equivalent of 100. The variable `\$b` is assigned the decimal value 5, which has a binary equivalent of 101.

The variable `\$c` is then assigned the result of performing a bitwise OR operation on `\$a` and `\$b`, which results in the binary value 101 (decimal 5). The binary representation of `\$c` is also shown using the `decbin()` function.

The variable `\$d` is then assigned the result of performing a logical OR operation on `\$a` and `\$b`, which results in the boolean value `true`. The boolean value of `\$d` is output using a ternary operator to display either "true" or "false".

When this code is run, the output will be:

```a = 4 (binary 100)
b = 5 (binary 101)
a | b = 5 (binary 101)
a || b = true```

This output shows the original values of `\$a` and `\$b` in both decimal and binary format, the result of the bitwise OR operation on `\$a` and `\$b` (also in both decimal and binary format), and the result of the logical OR operation on `\$a` and `\$b`.