Php 获取foreach中以前的数组值
我的阵列:Php 获取foreach中以前的数组值,php,arrays,Php,Arrays,我的阵列: $arr = array("jan","feb","mar","apr","mei","jun","jul","agu","sep","okt","nov","des"); 然后我做一个foreach foreach($arr as $ar){ echo $ar; } 这将输出jan到des 我的问题是如何在当前键中显示以前的值 例如,当我到达二月时,我也想显示一月,当我到达七月时,我想显示六月,等等。您可以使用这些键获取上一个键 foreach($arr as $key =
$arr = array("jan","feb","mar","apr","mei","jun","jul","agu","sep","okt","nov","des");
然后我做一个foreach
foreach($arr as $ar){
echo $ar;
}
这将输出jan到des
我的问题是如何在当前键中显示以前的值
例如,当我到达二月时,我也想显示一月,当我到达七月时,我想显示六月,等等。您可以使用这些键获取上一个键
foreach($arr as $key => $ar){
$prev = $arr[$key-1];
echo "previous value -" .$prev;
}
您还可以将以下内容作为内部数组指针:
$transport = array('foot', 'bike', 'car', 'plane');
$mode = current($transport); // $mode = 'foot';
$mode = next($transport); // $mode = 'bike';
$mode = next($transport); // $mode = 'car';
$mode = prev($transport); // $mode = 'bike';
$mode = end($transport); // $mode = 'plane';
($i=0;$i 0)的{
回声$arr[$i-1]
}
}
请参阅此问题和。foreach($arr as$key=>$ar){
//检查我们不在一月(否则我们得到$key=-1,这不起作用)
如果($key!=0){
//打印上个月,然后打印本月
回声$arr[$key-1].-'.$ar.
;
}
}
//或者,如果您希望能够滚动数年,那么:
$last_key=end(数组_key($arr));
foreach($arr as$key=>$ar){
//检查一下,我们不是在一月
如果($key!=0){
//打印上个月,然后打印本月
回声$arr[$key-1].-'.$ar.
;
}否则{
回显$arr[$last_key].-'.$ar.
;
}
}
更具动态性
$arr = array(
"jan",
"feb",
"mar",
"apr",
"mei",
"jun",
"jul",
"agu",
"sep",
"okt",
"nov",
"des"
);
$arr2 = $arr;
foreach ($arr as $k => $currVal) {
unset($arr2[$k]);
foreach ($arr2 as $k => $v) {
$nextVal = $v;
break;
}
echo "next val: " . $nextVal;
echo "current val: " . $currVal;
}
这不是应该显示当前和以前的吗?这不会在第一次迭代中消失吗?这不会在循环中发生。。但它可能会发生。它是相对于当前元素的内部指针的。这仅在键为整数且按顺序排列时有效。这还有一个额外的优点,可以用于具有字符串和非顺序索引的数组。
for ( $i = 0; $i <count($arr); $i++) {
echo $arr[$i]
if($i > 0){
echo $arr[$i-1]
}
}
reset($array);
while($val=current($array))
{
var_dump($val); // current
var_dump(prev($array)); // previous
next($array); // back to current
next($array); // next
}
foreach($arr as $key => $value){
if ($key > 0) {
echo $arr[$key-1];
}
echo $value;
}
foreach ($arr as $key => $ar) {
//check we aren't on jan (otherwise we get $key = -1 which doesn't work)
if ($key != 0) {
//print previous month followed by current month
echo $arr[$key - 1] . '-' . $ar . '<br />';
}
}
//OR, if you want to be able to roll through years then:
$last_key = end(array_keys($arr));
foreach ($arr as $key => $ar) {
//check we aren't on jan
if ($key != 0) {
//print previous month followed by current month
echo $arr[$key - 1] . ' - ' . $ar . '<br />';
} else {
echo $arr[$last_key] . ' - ' . $ar . '<br />';
}
}
$arr = array(
"jan",
"feb",
"mar",
"apr",
"mei",
"jun",
"jul",
"agu",
"sep",
"okt",
"nov",
"des"
);
$arr2 = $arr;
foreach ($arr as $k => $currVal) {
unset($arr2[$k]);
foreach ($arr2 as $k => $v) {
$nextVal = $v;
break;
}
echo "next val: " . $nextVal;
echo "current val: " . $currVal;
}