php function return a Boolean and use it on condition

Question

im not sure on how i am going to explain this correctly.

I wanted a function to validate a string which i figured correctly.

But i want the function to return a boolean value.

And outside a function i need to make a condition that if the function returned false, or true that will do something. Here's my code.

i am not sure if this is correct.

<?php
$string1 = 'hi';
function validatestring($myString, $str2) {
    if(!empty($myString)) {
        if(preg_match('/^[a-zA-Z0-9]+$/', $str2)) {
            }
    }
    else {
        return false;
    }
}

if(validatestring == FALSE) {
    //put some codes here
}
else {
    //put some codes here
}
?>

EDIT : Now what if there are more than 1 condition inside the function?

<?php
$string1 = 'hi';
function validatestring($myString, $myString2) {
    if(!empty($myString)) {
        if(preg_match('/^[a-zA-Z0-9]+$/', $str2)) {
            return true;
        }
        else {
            retun false;
        }
    }
    else {
        return false;
    }
}

if(validatestring($myString, $myString2) === FALSE) {
    //put some codes here
}
else {
    //put some codes here
}
?>

if(validatestring($myString)){ ?

Damien Pirsy
– Damien Pirsy

2014-03-20 06:10:30 +00:00
Commented Mar 20, 2014 at 6:10 — Damien Pirsy
– Damien Pirsy, Commented Mar 20, 2014 at 6:10
you are not passing argument to function ...

user1844933
– user1844933

2014-03-20 06:10:49 +00:00
Commented Mar 20, 2014 at 6:10 — user1844933
– user1844933, Commented Mar 20, 2014 at 6:10
and use === instead of ==

dayuloli
– dayuloli

2014-03-20 06:10:55 +00:00
Commented Mar 20, 2014 at 6:10 — dayuloli
– dayuloli, Commented Mar 20, 2014 at 6:10

Realitätsverlust · Accepted Answer · 2014-03-20 06:11:58Z

2

Functions need brackets and parameter. You dont have any of them.

This would be correct:

if(validatestring($myString) === false) {
    //put some codes here
}

An easier and more elegant method would be this:

if(!validatestring($myString)) {
    //put some codes here
}

answered Mar 20, 2014 at 6:11

Realitätsverlust

3,9532 gold badges27 silver badges46 bronze badges

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

7 Comments

CudoX Over a year ago

so, i won't need to call the function first? e.g validatestring($myString); if(//the condition) {}

Realitätsverlust Over a year ago

The function will be evaluated first because the value is needed to check for the if. The value which the functions returns will be used in the condition. So you dont have to call it first, no, the above method is valid, common and more professional than evaluating the function first, save it in a variable and then use the variable in the condition.

CudoX Over a year ago

so since it is needed for the if then the function will be evaluated without calling it then make the if, was that right?

Realitätsverlust Over a year ago

You are calling the function INSIDE the if condition. This is like you were calling it outside. It would be even possible to assign the variable inside the if like if(($var = validatestring($myString)) === false) {}.

Realitätsverlust Over a year ago

Thats valid yes. A function can only return once, after it, it aborts and will continue with the usual code. So you can put millions of return in a function, it will ALWAYS only return one value.

|

dayuloli · Accepted Answer · 2014-03-20 06:11:33Z

1

<?php
$string1 = 'hi';
function validatestring($myString) {
    if(!empty($myString)) {
        return true;
    }
    else {
        return false;
    }
}

if(validatestring($string1) === FALSE) {
    //put some codes here
}
else {
    //put some codes here
}
?>

answered Mar 20, 2014 at 6:11

dayuloli

17.2k18 gold badges76 silver badges133 bronze badges

Comments

Damien Pirsy · Accepted Answer · 2014-03-20 06:13:55Z

1

Sidenote, since empty() already returns false ,you could simplify by doing:

function validateString($string){
  return !empty($string);
}

if(validateString($myString){
  // ok
}
else {
 // not ok
}

To make a check and test later:

 $check = validateString($myString);

 if($check){ }

There's no need to check == false or === false, the function already returns a boolean, it would be redundant.

answered Mar 20, 2014 at 6:13

Damien Pirsy

25.5k8 gold badges72 silver badges77 bronze badges

Comments

vitthal · Accepted Answer · 2014-03-20 06:19:33Z

-1

store $string1 to $myString in the function myString=string1

<?php
$string1 = 'hi';
function validatestring($myString) {
        myString=string1;
    if(!empty($myString)) {
        return true;
    }
    else {
        return false;
    }
}

if(validatestring() === FALSE) {
    //put some codes here
}
else {
    //put some codes here
}
?>

answered Mar 20, 2014 at 6:19

vitthal

115 bronze badges

1 Comment

Damien Pirsy Over a year ago

What??? Apart from the syntax error, $string1 is undefined inside the scope of the function!

Collectives™ on Stack Overflow

php function return a Boolean and use it on condition

4 Answers 4

7 Comments

Comments

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

7 Comments

Comments

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related