I am writing a SQL query creator using some parameters. In Java, it's very easy to detect the last element of an array from inside the for loop by just checking the current array position with the array length.
for(int i=0; i< arr.length;i++){
boolean isLastElem = i== (arr.length -1) ? true : false;
}
In PHP they have non-integer indexes to access arrays. So you must iterate over an array using a foreach loop. This becomes problematic when you need to take some decision (in my case to append or/and parameter while building query).
I am sure there must be some standard way of doing this.
How do you solve this in PHP?
This should be the easy way to find the last element:
foreach ( $array as $key => $a ) {
if ( end( array_keys( $array ) ) == $key ) {
echo "Last element";
} else {
echo "Just another element";
}
}
Reference : Link
You could also try this to make your query... shown here with INSERT
<?php
$week=array('one'=>'monday','two'=>'tuesday','three'=>'wednesday','four'=>'thursday','five'=>'friday','six'=>'saturday','seven'=>'sunday');
$keys = array_keys($week);
$string = "INSERT INTO my_table ('";
$string .= implode("','", $keys);
$string .= "') VALUES ('";
$string .= implode("','", $week);
$string .= "');";
echo $string;
?>
Another way to go is to remember the previous loop cycle result and use that as the end result:
$result = $where = "";
foreach ($conditions as $col => $val) {
$result = $where .= $this->getAdapter()->quoteInto($col.' = ?', $val);
$where .= " AND ";
}
return $this->delete($result);
You can still use that method with associative arrays:
$keys = array_keys($array);
for ($i = 0, $l = count($array); $i < $l; ++$i) {
$key = $array[$i];
$value = $array[$key];
$isLastItem = ($i == ($l - 1));
// do stuff
}
// or this way...
$i = 0;
$l = count($array);
foreach ($array as $key => $value) {
$isLastItem = ($i == ($l - 1));
// do stuff
++$i;
}
One way could be to detect if the iterator has next. If there is no next attached to the iterator it means you are in the last loop.
foreach ($some_array as $element) {
if(!next($some_array)) {
// This is the last $element
}
}
I kinda like the following as I feel it is fairly neat. Let's assume we're creating a string with separators between all the elements: e.g. a,b,c
$first = true;
foreach ( $items as $item ) {
$str = ($first)?$first=false:", ".$item;
}
If I understand you, then all you need is to reverse the array and get the last element by a pop command:
$rev_array = array_reverse($array);
echo array_pop($rev_array);
you can do a count().
for ($i=0;$i<count(arr);$i++){
$i == count(arr)-1 ? true : false;
}
or if you're looking for ONLY the last element, you can use end().
end(arr);
returns only the last element.
and, as it turns out, you CAN index php arrays by integers. It's perfectly happy with
arr[1];
foreach ($array as $key => $value) {
$class = ( $key !== count( $array ) -1 ) ? " class='not-last'" : " class='last'";
echo "<div{$class}>";
echo "$value['the_title']";
echo "</div>";
}
Assuming you have the array stored in a variable...
foreach($array as $key=>$value)
{
echo $value;
if($key != count($array)-1) { echo ", "; }
}
You could also do something like this:
end( $elements );
$endKey = key($elements);
foreach ($elements as $key => $value)
{
if ($key == $endKey) // -- this is the last item
{
// do something
}
// more code
}
I personally use this kind of construction which enable an easy use with html < ul > and < li > elements : simply change the equality for an other property...
The array cannot contains false items but all the others items which are cast into the false boolean.
$table = array( 'a' , 'b', 'c');
$it = reset($table);
while( $it !== false ) {
echo 'all loops';echo $it;
$nextIt = next($table);
if ($nextIt === false || $nextIt === $it) {
echo 'last loop or two identical items';
}
$it = $nextIt;
}
If you need to do something for every element except either the first or the last and only if there is more than one element in the array, I prefer the following solution.
I know there are many solutions above and posted months/one year before mine, but this is something I feel is fairly elegant in its own right. The check every loop is also a boolean check as opposed to a numeric "i=(count-1)" check, which may allow for less overhead.
The structure of the loop may feel awkward, but you can compare it to the ordering of thead (beginning), tfoot (end), tbody (current) in HTML table tags.
$first = true;
foreach($array as $key => $value) {
if ($first) {
$first = false;
// Do what you want to do before the first element
echo "List of key, value pairs:\n";
} else {
// Do what you want to do at the end of every element
// except the last, assuming the list has more than one element
echo "\n";
}
// Do what you want to do for the current element
echo $key . ' => ' . $value;
}
For instance, in web development terms, if you want to add a border-bottom to every element except the last in an unordered list (ul), then you can instead add a border-top to every element except the first (the CSS :first-child, supported by IE7+ and Firefox/Webkit supports this logic, whereas :last-child is not supported by IE7).
You can feel free to reuse the $first variable for each and every nested loop as well and things will work just fine since every loop makes $first false during the first process of the first iteration (so breaks/exceptions won't cause issues).
$first = true;
foreach($array as $key => $subArray) {
if ($first) {
$string = "List of key => value array pairs:\n";
$first = false;
} else {
echo "\n";
}
$string .= $key . '=>(';
$first = true;
foreach($subArray as $key => $value) {
if ($first) {
$first = false;
} else {
$string .= ', ';
}
$string .= $key . '=>' . $value;
}
$string .= ')';
}
echo $string;
Example output:
List of key => value array pairs:
key1=>(v1_key1=>v1_val1, v1_key2=>v1_val2)
key2=>(v2_key1=>v2_val1, v2_key2=>v2_val2, v2_key3=>v2_val3)
key3=>(v3_key1=>v3_val1)
For SQL query generating scripts, or anything that does a different action for the first or last elements, it is much faster (almost twice as fast) to avoid using unneccessary variable checks.
The current accepted solution uses a loop and a check within the loop that will be made every_single_iteration, the correct (fast) way to do this is the following :
$numItems = count($arr);
$i=0;
$firstitem=$arr[0];
$i++;
while($i<$numItems-1){
$some_item=$arr[$i];
$i++;
}
$last_item=$arr[$i];
$i++;
A little homemade benchmark showed the following:
test1: 100000 runs of model morg
time: 1869.3430423737 milliseconds
test2: 100000 runs of model if last
time: 3235.6359958649 milliseconds
So, if your array has unique array values, then determining last iteration is trivial:
foreach($array as $element) {
if ($element === end($array))
echo 'LAST ELEMENT!';
}
As you see, this works if last element is appearing just once in array, otherwise you get a false alarm. In it is not, you have to compare the keys (which are unique for sure).
foreach($array as $key => $element) {
end($array);
if ($key === key($array))
echo 'LAST ELEMENT!';
}
Also note the strict coparision operator, which is quite important in this case.
<?php foreach($have_comments as $key => $page_comment): ?>
<?php echo $page_comment;?>
<?php if($key+1<count($have_comments)): ?>
<?php echo ', '; ?>
<?php endif;?>
<?php endforeach;?>
How about using "end"? http://php.net/manual/en/function.end.php
Don't add a comma after the last value:
The array:
$data = ['lorem', 'ipsum', 'dolor', 'sit', 'amet'];
The function:
$result = "";
foreach($data as $value) {
$result .= (next($data)) ? "$value, " : $value;
}
The result:
print $result;
lorem, ipsum, dolor, sit, amet
You could get the value of the last key of the array using end(array_keys($array)) and compare it to the current key:
$last_key = end(array_keys($array));
foreach ($array as $key => $value) {
if ($key == $last_key) {
// last element
} else {
// not last element
}
}
SINCE PHP 7.3 UNTIL NOW You could get the value of the last key of the array using array_key_last($array) and compare it to the current key:
$last_key = array_key_last($array);
foreach ($array as $key => $value) {
if ($key == $last_key) {
// last element
} else {
// not last element
}
}
When toEnd reaches 0 it means it is at the last iteration of the loop.
$toEnd = count($arr);
foreach($arr as $key=>$value) {
if (0 === --$toEnd) {
echo "last index! $value";
}
}
The last value is still available after the loop, so if you just want to use it for more stuff after the loop this is better:
foreach($arr as $key=>$value) {
//something
}
echo "last index! $key => $value";
If you do not want to treat the last value as special inside loops. This should be faster if you have large arrays. (If you reuse the array after the loop inside the same scope you have to "copy" the array first).
//If you use this in a large global code without namespaces or functions then you can copy the array like this:
//$array = $originalArrayName; //uncomment to copy an array you may use after this loop
//end($array); $lastKey = key($array); //uncomment if you use the keys
$lastValue = array_pop($array);
//do something special with the last value here before you process all the others?
echo "Last is $lastValue", "\n";
foreach ($array as $key => $value) {
//do something with all values before the last value
echo "All except last value: $value", "\n";
}
//do something special with the last value here after you process all the others?
echo "Last is $lastValue", "\n";
And to answer your original question "in my case to append or/and parameter while building query"; this will loop over all the values, then join them together to a string with " and " between them but not before the first value or after the last value:
$params = [];
foreach ($array as $value) {
$params[] = doSomething($value);
}
$parameters = implode(" and ", $params);
to get first and last element from foreach array
foreach($array as $value) {
if ($value === reset($array)) {
echo 'FIRST ELEMENT!';
}
if ($value === end($array)) {
echo 'LAST ITEM!';
}
}
More easy by end() function is an inbuilt function in PHP and is used to find the last element of the given array. The end() function changes the internal pointer of an array to point to the last element and returns the value of the last element.
Below is an example with non integer index:
<?php
$arr = array(
'first' =>
array('id' => 1, 'label' => 'one'),
'second' =>
array('id' => 2, 'label' => 'two'),
'last' =>
array('id' => 9, 'label' => 'nine')
);
$lastIndexArr = end($arr);
print_r($lastIndexArr);
Check here the last array as an output.
Try this simple solution
$test = ['a' => 1, 'b' => 2, 'c' => 3];
$last_array_value = end($test);
foreach ($test as $key => $value) {
if ($value === $last_array_value) {
echo $value; // display the last value
} else {
echo $value; // display the values that are not last elements
}
}
It sounds like you want something like this:
$array = array(
'First',
'Second',
'Third',
'Last'
);
foreach($array as $key => $value)
{
if(end($array) === $value)
{
echo "last index!" . $value;
}
}
There are already many answers, but it's worth to look into iterators as well, especially as it has been asked for a standard way:
$arr = range(1, 3);
$it = new CachingIterator(new ArrayIterator($arr));
foreach($it as $key => $value)
{
if (!$it->hasNext()) echo 'Last:';
echo $value, "\n";
}
You might find something that does work more flexible for other cases, too.
Here's my solution: Simply get the count of your array, minus 1 (since they start in 0).
$lastkey = count($array) - 1;
foreach($array as $k=>$a){
if($k==$lastkey){
/*do something*/
}
}
why so complicated?
foreach($input as $key => $value) {
$ret .= "$value";
if (next($input)==true) $ret .= ",";
}
This will add a , behind every value except the last one!
Here's another way you could do it:
$arr = range(1, 10);
$end = end($arr);
reset($arr);
while( list($k, $v) = each($arr) )
{
if( $n == $end )
{
echo 'last!';
}
else
{
echo sprintf('%s ', $v);
}
}
You can dirctly get last index by:
$numItems = count($arr);
echo $arr[$numItems-1];
I have a strong feeling that at the root of this "XY problem" the OP wanted just implode() function.
As your intention of finding the EOF array is just for the glue. Get introduced to the below tactic. You need not require the EOF:
$given_array = array('column1'=>'value1',
'column2'=>'value2',
'column3'=>'value3');
$glue = '';
foreach($given_array as $column_name=>$value){
$where .= " $glue $column_name = $value"; //appending the glue
$glue = 'AND';
}
echo $where;
o/p:
column1 = value1 AND column2 = value2 AND column3 = value3
Source: Stackoverflow.com