what is the use of . operator at the end of variable php

Question

I found the following code in http://in3.php.net/manual/en/function.chr.php

<?php 
function randPass($len) 
{ 
 $pw = ''; //intialize to be blank 
 for($i=0;$i<$len;$i++) 
 { 
   switch(rand(1,3)) 
   { 
     case 1: $pw.=chr(rand(48,57));  break; //0-9 
     case 2: $pw.=chr(rand(65,90));  break; //A-Z 
     case 3: $pw.=chr(rand(97,122)); break; //a-z 
   } 
 } 
 return $pw; 
} 
?> 

Example: 

<?php 
 $password = randPass(10); //assigns 10-character password 
?>

Could some kindly explain me the use or effect of a . after $pw .I tried looking for similar question,but could not find one.If there is any related question,plz provide link.

Thanks

You have to read the code as `$pw .= chr(...);`. `.=` is an operator. — Felix Kling, May 02 '13 at 18:26
See: http://stackoverflow.com/questions/3737139/reference-what-does-this-symbol-mean-in-php — nickb, May 02 '13 at 18:26

score 1 · Answer 1 · answered May 02 '13 at 18:24

1

. is string concatenation.

$a = 'hello';
$b = 'there';

then

echo $a . $b;

prints

hellothere

answered May 02 '13 at 18:24

mzedeler

4,177
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score 0 · Answer 2 · answered May 02 '13 at 18:24

0

Concatenation Operator.

$a = "Hello ";
$a .= "World!"; 
// $a = Hello World!

$a = "Hello ";
$b = "there ";
$c = "stack ";
$d = "overflow ";
$a .= $b;
$a .= $c;
$a .= $d;
echo $a;

// $a = Hello there stack overflow

answered May 02 '13 at 18:24

brbcoding

13,378
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Why the downvote/no comment? This is definitely correct. – brbcoding May 02 '13 at 18:29
1

Indeed. Not only it was the 1st answer, it's also correct. Maybe you should flag it (if the downvote comes from another answer author, this is unfair) – Déjà vu May 02 '13 at 18:33

Siamak Motlagh · Answer 3 · 2013-05-02T18:43:51.373

0

It use for Concatenation.
When you use it like this .= it concatenates the values.

$str = '';
$str .= 'My ';
$str .= 'Name ';
$str .= 'Is ';
$str .= 'Siamak.';
echo $str;

Output is : My Name Is Siamak.
In the other cases, for example in a loop:

$str = '';
$i=0;
while($i<10)
{
   $str .= $i;
   $i++;
}
echo $str;

And output is: 123456789

edited May 02 '13 at 18:43

answered May 02 '13 at 18:29

Siamak Motlagh

5,028
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score 0 · Answer 4 · answered May 02 '13 at 18:45

0

$a = 'hello';
$a .= ' world';

Is the same as:

$a = 'hello';
$a = $a . ' world';

answered May 02 '13 at 18:45

Marcos

1,240
10
20

score 0 · Answer 5 · answered May 02 '13 at 18:49

0

    $a = "Hi!";

    $a .= " I";
    $a .= " am";
    $a .= " new";
    $a .= " to";
    $a .= " PHP & StackOverflow";

echo $a;


//echos Hi! I am new to PHP & StackOverflow

.= simply appends

answered May 02 '13 at 18:49

Mayur

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what is the use of . operator at the end of variable php

5 Answers5