We can evaluate and combine multiple comparisons with logical operators. For example, we make a comparison of whether a variable is greater than 0 or less than 100 thanks to logical operators.

Let’s show the logical operators in a table:

Operator | Name | Usage | Explanation |
---|---|---|---|

! | Negative | !$a | Returns true if the value of $a is negative, or the other way around. |

&& | And | $a && $b | If the value of $a and $b is positive, TRUE returns positive, if either is negative, returns FALSE. |

|| | Or | $a || $b | Returns positive if the value of $a or the value of $b is positive. It is enough that one or both are positive. |

In an example of these, we said at the beginning; Let’s compare the value of a variable “if it is greater than 0 and less than 100”. The condition we apply for this is as follows: `$a > 0 && $a < 100`

This means if the variable `$a`

is greater than 0 and less than 100. If the number in `$a`

is between 0 and 100, the result of this condition will be positive.