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phpstringreplacesubstring
vikmalhotra
vikmalhotra

Reputation: 10071

Replace or insert characters into a string based on a numeric position in the string

Is there a function in PHP that takes in a string, a number (i), and a character (x), then replaces the character at position (i) with (x)?

If not, can somebody help me in implementing a function which can replace or insert a substring?

Upvotes: 33

Views: 76452

Answers (6)

mickmackusa
mickmackusa

Reputation: 47971

substr_replace() is capable of replacing n number of characters bytes starting from x offset (positive or negative) in a given string with another string and has an optional parameter for limiting the number of characters bytes consumed before injecting the replacement string.

Multibyte strings are fine to use, but the offset and length parameters will count each byte of the multibyte characters.

Examples: (Demo)

echo substr_replace('stack',  'i',    2,  1);  // stick
echo substr_replace('stack',  'u',   -3,  1);  // stuck
echo substr_replace('stack',  'o',    1,  2);  // sock
echo substr_replace('stack',  'ge',  -2,  2);  // stage
echo substr_replace('stack',  'bri',  0,  3);  // brick
echo substr_replace('stack',  'hre',  1, -1);  // shrek
echo substr_replace('stack',  'hre', -4, -1);  // shrek
echo substr_replace('stack',  'y',    3,  0);  // stayck   ...consume no bytes
echo substr_replace('stack',  'y',    3);      // stay     ...consume remaining bytes
echo substr_replace('voilà',  'ci',  -2);      // voilci   ...à has two bytes
echo substr_replace('voilà',  'ci',  -3);      // voici    ...à has two bytes
echo substr_replace('sûreté', '',     4);      // sûr      ...û has two bytes

Upvotes: 0

Amorim
Amorim

Reputation: 47

implode(':', str_split('1300', 2));

returns:

13:00

Also very nice for some credit card numbers like Visa:

implode(' ', str_split('4900000000000000', 4));

returns:

4900 0000 0000 0000

str_split — Convert a string to an array

Upvotes: 0

zerkms
zerkms

Reputation: 254975

I amazed why no one remember about substr_replace()

substr_replace($str, $x, $i, 1);

Upvotes: 16

codaddict
codaddict

Reputation: 455192

$str    = 'bar';
$str[1] = 'A';
echo $str; // prints bAr

or you could use the library function substr_replace as:

$str = substr_replace($str,$char,$pos,1);

Upvotes: 68

Emil Vikström
Emil Vikström

Reputation: 91963

function replace_char($string, $position, $newchar) {
  if(strlen($string) <= $position) {
    return $string;
  }
  $string[$position] = $newchar;
  return $string;
}

It's safe to treat strings as arrays in PHP, as long as you don't try to change chars after the end of the string. See the manual on strings:

Upvotes: 1

alex
alex

Reputation: 490373

Codaddict is correct, but if you wanted a function, you could try...

function updateChar($str, $char, $offset) {

   if ( ! isset($str[$offset])) {
       return FALSE;
   }

   $str[$offset] = $char;

   return $str;

}

It works!

Upvotes: 4

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