如果零浮点值作为字符串传递，则 empty() 返回 true

Question

MySQL with PHP can sometimes be annoying when decimals are returned as strings like with MYSQL functions. Is there a function to check if a variable is any of these in one?

null, (bool)false, (int)0, (float)0.00, (string)"", (string)"0", (string)"0.00", or (array)[].

empty() almost does the job but falls on these mysql decimal values sometimes returned as strings. isset() and is_null() operates differently in PHP 7 and 8. I am missing something like emptyish().

What does not work with empty():

if (empty($var)) // Doesn't work for decimal/floats passed as string "0.00"
if (!isset($var) || !$var) // Does not work in PHP 8 for an empty string
if ($var == 0) // Leaves a warning if $var is not declared

Answer 1

This zero/empty condition works the same way in both PHP 7 and 8 versions:

if (empty($var) || (float)$var == 0)

It checks if $var is any of the following: not set, null, (bool)false, (int)0, (float)0.00, (string)"", (string)"0", (string)"0.00", or (array)[]

And to substitute empty():

function nil(&$var) { // https://www.dictionary.com/browse/nil
  return (empty($var) || (float)$var == 0);
}

To be used like:

if (nil($var)) {
  echo 'The value is either not set, an empty string, empty array, null, or equals zero.';
}

Answer 2

Check this isset gettype

Isset checking on null and not empty value. Via gettype you can avoid type string.

if(isset($var) || gettype($v) !== 'string'){
.
.
.
}

Answer 3

use isset().

<?php
if(isset($var)){
  //$var is set
  if(!$var){
    //$var is 0
  } else if(empty($var)){
    //$var is empty
  } else {
    //code goes here
  }
}else{
  //$var is not set
}