PHP string based comparison function strcmp of and strcasecmp of use details
- 2020-06-03 05:55:31
- OfStack
The difference between "===" and "==" is simply that the former emphasizes that "identical(same, exactly the same)" requires one; The latter requires "equal" and the same value is sufficient. Or use strcmp, but this will tell you if two strings are equal, but not where they are different.
1 as good as possible! Equals, equals, compares two objects to see if they're equal, two objects, because they're not all strings, they're integers, and so on. Such as
$a = "joe";
$b = "jerry";
if ($a != $b)
{
echo " Not equal to the ";
}
else
{
echo " equal ";
}
If use! To return true, the types of the two objects must be strictly equal. Or use the = =,! = automatically converts the string to the appropriate type for comparison.
22 == "22"; // return true
22 === "22"; // return falsePHP Functions for string comparison: strcmp(),strcasecmp(),strncasecmp(), strncmp() They all are If the former is larger than the latter , Returns greater than 0 The integer; If the former is less than the latter, the return is less than 0 The integer; If the two are equal, returns 0.
1)strcmp Is used for Case sensitivity ( Case sensitive ) String comparison of:
2)echo strcmp("abcdd", "abcde"); // return 1 (>0), The comparison is "b" and "b"
3)strcasecmp For case-insensitive string comparisons:
4)echo strcasecmp("abcdd", "abcde"); // return -1 (<0), The comparison is "d" and "e"
strncmp Used to compare strings 1 Section, starting at the beginning of the string, at 3 Is the length to be compared:
echo strncmp("abcdd", "abcde", 3); // return 1 (>0), Comparison of the abc and abc
strncasecmp Used for case-insensitive comparison strings 1 Section, starting at the beginning of the string, at 3 Is the length to be compared:
echo strncasecmp("abcdd", "abcde", 3); // return 0, Comparison of the abc and abc, They are the same because they are case insensitive.
more 1 In this case, the comparison of string sizes alone does not meet our pre-determined requirements, such as business as usual 10.gif than 5.gif Large, but if you apply the above functions, it returns -1, It indicates that the 10.gif than 5.gif, In this case, php Two natural contrast functions are provided strnatcmp,strnatcasecmp :
echo strnatcmp("10.gif", "5.gif"); // return 1 (>0)
echo strnatcasecmp("10.gif", "5.gif"); // return 1 (>0)