String to byte array in php


Question

How can I get the byte array from some string which can contain numbers, letters and so on? If you are familiar with Java, I am looking for the same functionality of the getBytes() method.

I tried a snippet like this one:

for($i = 0; $i < strlen($msg); $i++){
    $data.=ord($msg[$i]);
        //or $data[]=ord($msg[$1]); 
}

but without success, so any kind of help will be appreciated.

PS: Why do I need this at all!? Well, I need to send a byte array via fputs() to a server written in Java...

1
45
10/9/2012 7:43:01 PM

Accepted Answer

@Sparr is right, but I guess you expected byte array like byte[] in C#. It's the same solution as Sparr did but instead of HEX you expected int presentation (range from 0 to 255) of each char. You can do as follows:

$byte_array = unpack('C*', 'The quick fox jumped over the lazy brown dog');
var_dump($byte_array);  // $byte_array should be int[] which can be converted
                        // to byte[] in C# since values are range of 0 - 255

By using var_dump you can see that elements are int (not string).

   array(44) {  [1]=>  int(84)  [2]=>  int(104) [3]=>  int(101) [4]=>  int(32)
[5]=> int(113)  [6]=>  int(117) [7]=>  int(105) [8]=>  int(99)  [9]=>  int(107)
[10]=> int(32)  [11]=> int(102) [12]=> int(111) [13]=> int(120) [14]=> int(32)
[15]=> int(106) [16]=> int(117) [17]=> int(109) [18]=> int(112) [19]=> int(101)
[20]=> int(100) [21]=> int(32)  [22]=> int(111) [23]=> int(118) [24]=> int(101)
[25]=> int(114) [26]=> int(32)  [27]=> int(116) [28]=> int(104) [29]=> int(101)
[30]=> int(32)  [31]=> int(108) [32]=> int(97)  [33]=> int(122) [34]=> int(121)
[35]=> int(32)  [36]=> int(98)  [37]=> int(114) [38]=> int(111) [39]=> int(119)
[40]=> int(110) [41]=> int(32)  [42]=> int(100) [43]=> int(111) [44]=> int(103) }

Be careful: the output array is of 1-based index (as it was pointed out in the comment)

75
9/23/2018 7:25:01 PM

print_r(unpack("H*","The quick fox jumped over the lazy brown dog"))

Array ( [1] => 54686520717569636b20666f78206a756d706564206f76657220746865206c617a792062726f776e20646f67 ) 

T = 0x54, h = 0x68, ...

You can split the result into two-hex-character chunks if necessary.


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