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POConvert a string to number and back to string?
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  1. POConvert a string to number and back to string?
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    copied!<p>I would like to know how I can convert a short ASCII string to a number (int, float, or numeric string). I saw a couple of <a href="https://stackoverflow.com/questions/3864185/string-to-number-and-back-algorithm">posts here</a> mentioned <a href="http://en.wikipedia.org/wiki/Perfect_hash_function" rel="nofollow noreferrer">perfect hashes</a> which seems like it <a href="https://stackoverflow.com/questions/2994921/perfect-hash-function-for-urls/3011311#3011311">might be what I need</a>. However, I'm not quite understanding the math for this.</p> <p><strong>How could you convert an ASCII string into a sequence of numbers and then back to a string?</strong></p> <p>As a side note, breaking a string down into it's ASCII character numbers is easy enough.</p> <pre><code>foreach(str_split($string) as $char) $number .= ord($char); </code></pre> <h3>Update</h3> <p>After more reading I came up with this. However, I'm wondering if there are anyways to <strong>shorten the number sequence</strong> so it's not quite as long.</p> <pre><code>class intnum { public static $charset = array( 32 =&gt; ' ', 33 =&gt; '!', 34 =&gt; '"', 35 =&gt; '#', 36 =&gt; '$', 37 =&gt; '%', 38 =&gt; '&amp;', 39 =&gt; "'", 40 =&gt; '(', 41 =&gt; ')', 42 =&gt; '*', 43 =&gt; '+', 44 =&gt; ',', 45 =&gt; '-', 46 =&gt; '.', 47 =&gt; '/', 48 =&gt; '0', 49 =&gt; '1', 50 =&gt; '2', 51 =&gt; '3', 52 =&gt; '4', 53 =&gt; '5', 54 =&gt; '6', 55 =&gt; '7', 56 =&gt; '8', 57 =&gt; '9', 58 =&gt; ':', 59 =&gt; ';', 60 =&gt; '&lt;', 61 =&gt; '=', 62 =&gt; '&gt;', 63 =&gt; '?', 64 =&gt; '@', 65 =&gt; 'A', 66 =&gt; 'B', 67 =&gt; 'C', 68 =&gt; 'D', 69 =&gt; 'E', 70 =&gt; 'F', 71 =&gt; 'G', 72 =&gt; 'H', 73 =&gt; 'I', 74 =&gt; 'J', 75 =&gt; 'K', 76 =&gt; 'L', 77 =&gt; 'M', 78 =&gt; 'N', 79 =&gt; 'O', 80 =&gt; 'P', 81 =&gt; 'Q', 82 =&gt; 'R', 83 =&gt; 'S', 84 =&gt; 'T', 85 =&gt; 'U', 86 =&gt; 'V', 87 =&gt; 'W', 88 =&gt; 'X', 89 =&gt; 'Y', 90 =&gt; 'Z', 91 =&gt; '[', 92 =&gt; '\\', 93 =&gt; ']', 94 =&gt; '^', 95 =&gt; '_', 96 =&gt; '`', 97 =&gt; 'a', 98 =&gt; 'b', 99 =&gt; 'c', 100 =&gt; 'd', 101 =&gt; 'e', 102 =&gt; 'f', 103 =&gt; 'g', 104 =&gt; 'h', 105 =&gt; 'i', 106 =&gt; 'j', 107 =&gt; 'k', 108 =&gt; 'l', 109 =&gt; 'm', 110 =&gt; 'n', 111 =&gt; 'o', 112 =&gt; 'p', 113 =&gt; 'q', 114 =&gt; 'r', 115 =&gt; 's', 116 =&gt; 't', 117 =&gt; 'u', 118 =&gt; 'v', 119 =&gt; 'w', 120 =&gt; 'x', 121 =&gt; 'y', 122 =&gt; 'z', 123 =&gt; '{', 124 =&gt; '|', 125 =&gt; '}' ); public static function fromNumber($number) { $string = ''; while($number) { $value = substr($number, 0, 2); $number = substr($number, 2); if($value &lt; 32) { $value .= substr($number, 0, 1); $number = substr($number, 1); } $string .= self::$charset[ (int) $value]; } return $string; } public static function fromString($string) { $number = ''; foreach(str_split($string) as $char) $number .= ord($char); return $number; } } $string = 'this is my test string to convert'; $number = intnum::fromString($string); $string = intnum::fromNumber($number); </code></pre>
 

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