How do we know the date is the last day of the month?

Question

I have a date saved in the database and, before I present it on the grid, I need to know if it’s the last day of the month.

I need this information to present it in a different color.

Answer 1

You can do it using the class PHP Datetime.

Example function:

function ultimoDia($data){
    $formato = 'd/m/Y'; // define o formato de entrada para dd/mm/yyyy
    $dt = DateTime::createFromFormat($formato, $data); // define data desejada
    if($dt->format('t') === $dt->format('d')){
        return true;
    }else{
        return false;
    }
}

Use:

var_dump(ultimoDia('17/08/2016')); // retorna bool(false)
var_dump(ultimoDia('30/08/2016')); // retorna bool(false)
var_dump(ultimoDia('31/08/2016')); // retorna bool(true)

Explanation:

$dt->format('t') returns the number of days of the month of the date referenced in the object

$dt->format('d') returns the day of the date referenced in the object

Answer 2

To get the last day of the month just that:

date("t", $data) == date("d", $data )

Can use gmdate if you prefer. Usually, to be used in loops, use numbers, as obtained by time() is much more effective than instantiating an object for that.

See working on IDEONE.

Using Mysql, for example, this is enough to get the date already in a certain format to work, without making numerous conversions:

SELECT UNIX_TIMESTAMP( data_evento );

The value returned is ready to use in date( ..., $data ).

Answer 3

Another option would be to use the function cal_days_in_month which returns the number of days of the month and year reported:

$days = cal_days_in_month(CAL_GREGORIAN, 8, 2016); // Retorna 31
echo (date('d') == $days)? 'Último dia':'';

The comparison is a simple Ternary Operator, that "printa" on the screen if the current day is the last day of the month, returned by the function cal_days_in_month

Answer 4

A funnier way to do with the relative format 'last day of' ;)

<?php
function isLastDay($day)
{
    return date( 'd', strtotime( $day ) ) == date( 'd', strtotime( 'last day of ' . date( 'M Y' , strtotime( $day ) ) ) );
}

isLastDay("30-06-1984"); //retorna true

See working