CODEWITHSUNDEEP
phpstring
sunjie
sunjie

Reputation: 2053

PHP: how to add a random character in a string at random position

How can i add a single random character (0-9 or a-z or - or _) at a random place in a string.

I can get the random position by following:

$random_position = rand(0,5);

Now How can i get a random number ( 0 to 9 ) OR random character (a to z) OR (-) OR (_)

and finally how i can add character to the above string in the above random position.

For example following is string:

$string = "abc123";
$random_position = 2;
$random_char = "_";

the new string should be: 

"a_bc123"

Upvotes: 8

Views: 7531

Answers (5)

Shef
Shef

Reputation: 45589

// map of characters
$map = '0123456789abcdefghijklmnopqrstuvwxyz-_';
// draw a random character from the map
$random_char_posotion = rand(0, strlen($map)-1); // say 2?
$random_char = $map[$random_char_posotion]; // 2

$str = 'abc123';

// draw a random position
$random_position = rand(0, strlen($str)-1); // say 3?

// inject the randomly drawn character
$str = substr($str, 0, $random_position).$random_char.substr($str,$random_position);

// output the result
echo $str; // output abc2123

Upvotes: 0

Mike
Mike

Reputation: 21659

$string = 'abc123';
$chars = 'abcdefghijklmnopqrstuvwxyz0123456789-_';
$new_string = substr_replace(
    $string,
    $chars[rand(0, strlen($chars)-1)],
    rand(0, strlen($string)-1),
    0
);

Upvotes: 1

YonoRan
YonoRan

Reputation: 1728

get the string length:

$string_length = strlen($string);//getting the length of the string your working with
$random_position = 2;//generate random position

generate the "random" character:

$characters = "abcd..xyz012...89-_";//obviously instead of the ... fill in all the characters - i was just lazy.

getting a random character out of the character string:

$random_char = substr($characters, rand(0,strlen($characters)), 1);//if you know the length of $characters you can replace the strlen with the actual length

breaking the string into 2 parts:

$first_part = substr($string, 0, $random_position);
$second_part = substr($string, $random_position, $string_length);

adding the random character:

$first_part .=  $random_char;

combining the two back together:

$new_string = $first_part.$second_part;

this may not be the best way, but I think it should do it...

Upvotes: 0

rrapuya
rrapuya

Reputation: 298

try something like this

<?php 

   $orig_string = "abc123";
   $upper =strlen($orig_string);
   $random_position = rand(0,$upper);
   $int = rand(0,51);
   $a_z = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
   $rand_char = $a_z[$int];


   $newstring=substr_replace($orig_string, $rand_char, $random_position, 0);

   echo 'original-> ' .$orig_string.'<br>';
   echo 'random-> ' .$newstring;
?>

Upvotes: 2

khattam
khattam

Reputation: 1174

$string = "abc123";
$random_position = rand(0,strlen($string)-1);
$chars = "qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM0123456789-_";
$random_char = $chars[rand(0,strlen($chars)-1)];
$newString = substr($string,0,$random_position).$random_char.substr($string,$random_position);
echo $newString;

Upvotes: 5

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