php check if user input is not space

Question

I have the following code to check user input:

if(isset($_POST['block_name']) && !empty($_POST['block_name'])) {
    $block->name = trim($_POST['block_name']);
}

But it accepts SPACE as valid input, so I changed to this:

if(isset($_POST['block_name']) && !empty($_POST['block_name']) && trim($_POST['block_name'])!='') {
        $block->name = trim($_POST['block_name']);
    }

I have found on web that I can use !=false as well. What is the difference and which is recommended.

Please read the documentation on empty first. Your question regarding false is also answered in the manual. — Jon
– Jon, Commented Jan 28, 2013 at 11:35

deceze · Accepted Answer · 2013-01-28 11:35:51Z

5

'' equals false in a loose comparison, so there's no real difference. Since '0' also equals false though, you may want to make your check more strict. empty is also just checking for false without triggering an error if the variable is not set. So isset && !empty is redundant to begin with.

Use:

if (isset($_POST['block_name']) && strlen(trim($_POST['block_name'])) > 0)

answered Jan 28, 2013 at 11:35

deceze♦

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1 Comment

Jamol Over a year ago

Thank you very much. I didn`t know trim($_POST['name']) do not accept 0. So now I am using if(isset($_POST['block_name']) && trim($_POST['block_name'])!='') so that 0 can also be accepted as a single character. Is there anything not so good in my code now?

Filippo oretti · Accepted Answer · 2013-01-28 11:35:11Z

0

you can check for the blank space with

  if( (strlen($string) == 1 ) && strpos(trim($string)," ")){

   echo "the string contains only a blank space";

  }

answered Jan 28, 2013 at 11:35

Filippo oretti

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2 Comments

Jon Over a year ago

What is this supposed to achieve?

Filippo oretti Over a year ago

@Jon wants the OP to check if the string has only a blank space inside?

Kalpesh · Accepted Answer · 2013-01-28 11:35:18Z

0

if(empty($_POST['block_name'])) should check:

"" (an empty string)
0 (0 as an integer)
0.0 (0 as a float)
"0" (0 as a string)
NULL
FALSE
array() (an empty array)
$var; (a variable declared, but without a value)

So, this should be best to go with: if(!empty(trim($_POST['block_name']))) { //proceed...

answered Jan 28, 2013 at 11:35

Kalpesh

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6 Comments

nice ass Over a year ago

I don't think empty works with expressions :) The manual says that only 5.5 supports them

Jamol Over a year ago

Fatal error: Can't use function return value in write context

Kalpesh Over a year ago

@jCloud .. it's good to assign $blockName = $_POST['block_name'] in a variable and then try empty actually if(!empty($blockName)).

Jamol Over a year ago

what will happen if $_POST['block_name'] is not set

Kalpesh Over a year ago

if it's not set, if condition will not satisfy.

|

G. N. Vashishtha · Accepted Answer · 2013-01-28 11:38:54Z

0

Use this conditional statement. I hope it will work.

if `$custSTR` is a sample string having spaces.

$custSTR = '     ';
if (strlen(trim(preg_replace('/\xc2\xa0/',' ',$custSTR))) == 0)
{
    echo "custSTR have space or empty.\n";
}

answered Jan 28, 2013 at 11:38

G. N. Vashishtha

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Comments

Jamol · Accepted Answer · 2013-01-28 11:59:57Z

0

After all I think this way is the best:

if(isset($_POST['block_name']) && strlen(trim($_POST['block_name'])) > 1) {
        $block->name = trim($_POST['block_name']);
    }
    else {
        $errors[] = "Please give a name for the new block. It should be at least 2 characters";
    }

Thanks for deceze for his answer.

answered Jan 28, 2013 at 11:59

Jamol

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