用于比较的PHP高级数组循环概念[重复]
问题描述：
This question already has an answer here:
I have a array like following...
array(2) {
["gender"]=>
array(2) {
[1]=>
string(4) "Male"
[2]=>
string(6) "Female"
}
["agegroup"]=>
array(3) {
[3]=>
string(7) "18 - 24"
[4]=>
string(7) "25 - 40"
[5]=>
string(7) "40 - 65"
}
}
This array is dynamic. As like 'gender' and 'age group' there can be any number of items. all these items are sub arrays (associative). I want to write a loop in php which loops from first array element against each in further array elements.
In the above example... the following output should come...
Male- 18-24
Male- 25-40
Male- 40-65
FeMale- 18-24
FeMale- 25-40
FeMale- 40-65
If array is like following...
array(2) {
["location"]=>
array(2) {
[A]=>
string(4) "New York"
[B]=>
string(6) "London"
}
["gender"]=>
array(2) {
[1]=>
string(4) "Male"
[2]=>
string(6) "Female"
}
["agegroup"]=>
array(3) {
[3]=>
string(7) "18 - 24"
[4]=>
string(7) "25 - 40"
[5]=>
string(7) "40 - 65"
}
}
then... output should be...
New York- Male- 18-24
New York- Male- 25-40
New York- Male- 40-65
New York- FeMale- 18-24
New York- FeMale- 25-40
New York- FeMale- 40-65
London- Male- 18-24
London- Male- 25-40
London- Male- 40-65
London- FeMale- 18-24
London- FeMale- 25-40
London- FeMale- 40-65
If the array length is defined I will be able to use foreach() to write snippet. But the array length of both parent and sub array is dynamic... can some one give me a hint of how to loop it to get the desired output ?
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答
function make ($arr, $pref = '') { // pref - saving path to this point
foreach (array_shift($arr) as $item) // take the 1st item of array and remove it
if($arr) make($arr,$pref . $item ." - "); // Call with sub-tree, add item to path
else echo $pref . $item ."
"; // Empty array - we are at leaf
}
make($arr);
for 2nd case result:
New York - Male - 18 - 24
New York - Male - 25 - 40
New York - Male - 40 - 65
New York - Female - 18 - 24
New York - Female - 25 - 40
New York - Female - 40 - 65
London - Male - 18 - 24
London - Male - 25 - 40
London - Male - 40 - 65
London - Female - 18 - 24
London - Female - 25 - 40
London - Female - 40 - 65