Help with For Loop. Values repeating
$team开发者_如何学JAVAs = array(1, 2, 3, 4, 5, 6, 7, 8);
$game1 = array(2, 4, 6, 8);
$game2 = array();
if teams[x]
is not in game1
then insert into game2
for($i = 0; $i < count($teams); $i++){
for($j = 0; $j < count($game1); $j++){
if($teams[$i] == $game1[$j]){
break;
} else {
array_push($game2, $teams[$i]);
}
}
}
for ($i = 0; $i < count($game2); $i++) {
echo $game2[$i];
echo ", ";
}
Im expecting the result to be:
1, 3, 5, 7,
However, im getting:
1, 1, 1, 1, 3, 3, 3, 3, 4, 5, 5, 5, 5, 6, 6, 7, 7, 7, 7, 8, 8, 8,
How can i improve this? Thanks
Others have already answered on how to use array_diff
.
Reason why your existing loop does not work:
if($teams[$i] == $game1[$j]){
// this is correct, if item is found..you don't add.
break;
} else {
// this is incorrect!! we cannot say at this point that its not present.
// even if it's not present you need to add it just once. But now you are
// adding once for every test.
array_push($game2, $teams[$i]);
}
You can use a flag to fix your existing code as:
for($i = 0; $i < count($teams); $i++){
$found = false; // assume its not present.
for($j = 0; $j < count($game1); $j++){
if($teams[$i] == $game1[$j]){
$found = true; // if present, set the flag and break.
break;
}
}
if(!$found) { // if flag is not set...add.
array_push($game2, $teams[$i]);
}
}
Your loop doesn't work because every time the element from $teams
is not equal to the element from $game1
, it adds the $teams
element to $game2
. That means each element is being added to $game2
multiple times.
Use array_diff
instead:
// Find elements from 'teams' that are not present in 'game1'
$game2 = array_diff($teams, $game1);
You can use PHP's array_diff():
$teams = array(1, 2, 3, 4, 5, 6, 7, 8);
$game1 = array(2, 4, 6, 8);
$game2 = array_diff($teams,$game1);
// $game2:
Array
(
[0] => 1
[2] => 3
[4] => 5
[6] => 7
)
精彩评论