PHP String comparison Methods

PHP built in String Comparisons (==,strcmp(),strcasecmp() )

The main drawback with this is that the program will produce unreliable results with many types of operands. Lets say for example you end up comparing a boolean value (true/False) or an integer with a string. What will the final result be? To combat this problem PHP has what is known as binary safe functions, where the function 'knows' what type of variable it is supposed to return.

strcmp()Used like This:
$result=strcmp($string1, $string2);

This function returns less than 0 if string1 is less than string2, greater than 0 if string1 is greater than string2 , and 0 if the strings are equal.

strcasecmp()Used like This:
$result=strcasemp($string1, $string2);

This is a case-insensitive version of strcmp and should be used where taking into account character case is not desirable, it returns exactly the same results as the PHP strcmp function. strncmp() Used like this:
$result=strncmp($string1, $string2,$int_num_chars);

This is the same as strcmp() except it obnly looks at the first int_num_chars or both strings.

strncasecmp() Used like this:
$result=strncasecmp($string1, $string2,$int_num_chars);

This is the same as strcnmp() it is case insensitive.

Why make your own Special String comparison Method?

This above is the output from the string comparison scoring function shown below. It is surprising when you test it how bulletproof the comparison method is as regards selecting similar and dissimilar strings. I have used it and other methods like it many times. You are free to use this PHP string comparison code yourself, the code has been placed in a text box to make cut and paste easier. A link back to www.webmaster-a.com would be appreciated!

Fuzzy Logic String Comparison Code

To use it you can put in sample strings on this page and decide on a threshold value for the score which indicates a level of similarity to the strings which corresponds to the level of recognition you need.

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