Syntax: orderByDescending ([{(v, k) ==> key} [, {(a, b) ==> diff}]])
Three methods are defined to extend the type {@link OrderedEnumerable}, which is the return type of this method. These three methods, namely {@link OrderedEnumerable::thenBy thenBy}, {@link OrderedEnumerable::thenByDescending thenByDescending} and {@link OrderedEnumerable::thenByDir thenByDir}, enable you to specify additional sort criteria to sort a sequence. These methods also return an OrderedEnumerable, which means any number of consecutive calls to thenBy, thenByDescending or thenByDir can be made.
Because OrderedEnumerable inherits from Enumerable, you can call {@link orderBy}, {@link orderByDescending} or {@link orderByDir} on the results of a call to orderBy, orderByDescending, orderByDir, thenBy, thenByDescending or thenByDir. Doing this introduces a new primary ordering that ignores the previously established ordering.
This method performs an unstable sort; that is, if the keys of two elements are equal, the order of the elements is not preserved. In contrast, a stable sort preserves the order of elements that have the same key. Internally, {@link usort} is used.
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public orderByDescending ( callable | null $keySelector = null, callable | integer | null $comparer = null ) : |
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| $keySelector | callable | null | {(v, k) ==> key} A function to extract a key from an element. Default: value. |
| $comparer | callable | integer | null | {(a, b) ==> diff} Difference between a and b: <0 if a<b; 0 if a==b; >0 if a>b. Can also be a combination of SORT_ flags. |
| return | ||
public function orderByDescending($keySelector = null, $comparer = null)
{
return $this->orderByDir(true, $keySelector, $comparer);
}