PHP: Why do we need string comparison function?
The comparision operators &开发者_开发知识库lt; <= > >=
can be applied for strings as well. So why do we need special function for string comparision: strcmp
?
Because there are several variations:
Depending on the function, the answer to these questions vary:
- Is it case sensitive? (
strcmp
vsstrcasecmp
,strnatcmp
vsstrnatcasecmp
) - Depends it depend on the locale? (
strcoll
does) - Can I specify a collation? (
strcoll
is affected bysetlocale
)
Additionaly, the comparison operators also give true
or false
. strcmp
gives an integer so it can encode simultaneously whether there's identity (return 0) or, if it not, which is is bigger (depending on whether the value is positive or negative).
Although there are no overloads in PHP for strcmp, strcmp results in 3 different values
-1 for less than, 0 for equals and +1 for greater than the compared string. With < = <= > >=
you will have (sometimes) to do multiple checks one after another.
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