Compare strings in PHP excluding Null or empty values [duplicate]

Question

I have a simple question about comparing strings in PHP.

I want to know if two strings (also applicable in any other type) are equal, but I want to exclude null or empty values of the comparison, so, I'm doing this:

if (!empty($var) && $var == $varToCompare) {
    //do stuff
}

It's working fine, but I'd like to know if there exists some operator or function to do this avoiding the empty() part.

My Background: I'd like to know this in a generic way, but here is my background to clarify. I have two or more variables and I need to compare them with variables in my Database, but if I have a NULL in my database and my var is also NULL (or a empty string) I expect false. Even using the === operator if the two strings are NULL or something like "" I receive true. See the example:

$myVars = $this->getArrayOfVars();
$var1 = $myDB->getVar1();// could be null or ""
$var2 = $myDB->getVar2();// could be null or ""
if ((!empty($var1) && $var1 == $myVars[1]) || (!empty($var2) && $var2 == $myVars[2])) {
    //do stuff
    // I just enter here when the strings are equal, but avoiding the null or empty values
}

I checked the docs, but didn't find anything. Someone knows a function that can do this?

Keep in mind that both empty(0) and empty('0') are true. — VolkerK
– VolkerK, Commented Jul 13, 2015 at 13:50
What if in your getArrayOfVars() method if you have a null or "" replace them by " " (space) whith that you will not need the first part of the test (!empty($var)) ? — Maraboc
– Maraboc, Commented Jul 13, 2015 at 14:01
@JayBlanchard. Yes, empty() is good to me, but I belive that the syntax using this is a little hard to read and a function as strcmpIgnoringEmpty() or something would be more readable — James
– James, Commented Jul 13, 2015 at 14:17

Dhinju Divakaran · Accepted Answer · 2015-07-13 13:51:09Z

2

Try is_null() and strcmp() ie,

if(strcmp($var,"")!=0 || is_null($var)){//strcmp returns 0 when strings are equal
}

answered Jul 13, 2015 at 13:51

Dhinju Divakaran

9031 gold badge8 silver badges11 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Random · Accepted Answer · 2015-07-13 14:15:23Z

1

The best practice would be to make your own function :

/** return false if any parameter is empty() or $var1 !== $var2 **/
function strictlyEqualAndNotNull($var1, $var2) {
    return (!empty($var1) && $var1 === $var2);
}

which gives :

$myVars = $this->getArrayOfVars();
$var1 = $myDB->getVar1();// could be null or ""
$var2 = $myDB->getVar2();// could be null or ""
if (strictlyEqualAndNotNull($var1, $myVars[1]) || 
    strictlyEqualAndNotNull($var2, $myVars[2])) {
    // do stuff
    // You will enter here when the strings are equal, but avoiding the null or empty values
}

edited Jul 13, 2015 at 14:15

answered Jul 13, 2015 at 14:08

Random

3,2551 gold badge18 silver badges25 bronze badges

2 Comments

James Over a year ago

I was looking for a built-in function for this, but apparently create my own is indeed the best option.

Random Over a year ago

Yeah, it is too specific to be a built-in function (in PHP... it may exist on Java's StringUtils...)

t1gor · Accepted Answer · 2015-07-13 13:58:28Z

0

Why not using strict comparison? Like $one === $two? In case one of them will be string and the other not, it will not work. Link: http://php.net/manual/en/language.operators.comparison.php

answered Jul 13, 2015 at 13:58

t1gor

1,28212 silver badges25 bronze badges

4 Comments

Random Over a year ago

But it won't work as asked, i.e if $one is NULL and $two is NULL, the test must return false, whereas $one === $two will return true...

t1gor Over a year ago

The question was about comparing strings, right? So strings are not null by default.

Random Over a year ago

but it is explicitly said "I want to exclude null or empty values of the comparison"

James Over a year ago

@t1gor. I know that strings are not NULL by default, but I'm trying to avoid NULL and empty strings (""," ","0", etc...). Thx anyway!

Ramyz · Accepted Answer · 2015-07-13 14:06:55Z

-1

just put @ sign in front of the string instated of empty()

if (@$var && $var == $varToCompare) {
        //do stuff
}



$myVars = $this->getArrayOfVars();
$var1 = $myDB->getVar1();// could be null or ""
$var2 = $myDB->getVar2();// could be null or ""
if ((@$var1 && $var1 == $myVars[1]) || (@$var2 && $var2 == $myVars[2])) {
    //do stuff
    // I just enter here when the strings are equal, but avoiding the null or empty values
}

edited Jul 13, 2015 at 14:06

answered Jul 13, 2015 at 14:05

Ramyz

4226 silver badges13 bronze badges

1 Comment

t1gor Over a year ago

Please avoid using @. It suppresses errors and makes you code less maintainable.

Collectives™ on Stack Overflow

Compare strings in PHP excluding Null or empty values [duplicate]

4 Answers 4

Comments

2 Comments

4 Comments

1 Comment

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

2 Comments

4 Comments

1 Comment

Linked

Related