function mycompare($a, $b) {
if ($a == $b) return 0;
return ($a > $b) ? -1 : 1;
}
$a = array(4 => "four", 3 => "three", 20 => "twenty", 10 => "ten");
uksort($a, mycompare);
while(list($key, $value) = each($a)) {
echo "$key: $value\n";
}
This example would display: 20: twenty 10: ten 4: four 3: three
函数usort()
描述:
以自定义的方式以value排列
void usort (array array, function cmp_function);
This function will sort an array by its values using a user-supplied comparison function. If the array you wish to sort needs to be sorted by some non-trivial criteria, you should use this function. Example 1. usort() example
function cmp($a,$b) {
if ($a == $b) return 0;
return ($a > $b) ? -1 : 1;
}
$a = array(3,2,5,6,1);
usort($a, cmp);
while(list($key,$value) = each($a)) {
echo "$key: $value\n";
}
This example would display: 0: 6 1: 5 2: 3 3: 2 4: 1 Obviously in this trivial case the rsort() function would be more appropriate.
BC (Arbitrary Precision) Functions
函数bcadd()
描述:
Add two arbitrary precision numbers
string bcadd (string left operand, string right operand, int [ scale ]); 左面的字符加右面的字符,返回一个字符。
函数bccomp()
描述:
int bccomp (string left operand, string right operand, int [ scale ]);
左面的字符和右面的字符进行比较,如果相等的话返回0,如果左面的比右面的长返回+1,右面的比左面的长返回-1
函数bcdiv()
描述:
Divide two arbitrary
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