I've read on a web page, explaining that in PHP it is must faster execution to do a for loop than a foreach. This is new to me, but I would like to test this for himself. How do I convert a foreach into a for loop in PHP? Using the one below as an example:
foreach ($station->ITEMS->ITEM as $trips=>$trip) {
$ny_trips[$trips] = $trip;
}
I've seen for loops in PHP, but not using 'as' in them. So I'm not sure how the above would look in PHP as a for loop. Would it also require doing a count() of $station->ITEMS->ITEM? Thanks!
Assuimg the keys on the array are a perfect numerical sequence starting at 0 then this is what you are looking for.
for($x = 0, $nItems = count($station->ITEMS->ITEM); $x<$nItems; $x++) {
$ny_trips[$x] = $station->ITEMS->ITEM[$x];
}
If the keys are non-numeric then or not in perfect order then you need to do something like this.
$keys = array_keys($station->ITEMS->ITEM);
for($x = 0, $nItems = count($station->ITEMS->ITEM);$x < $nItems; $x++) {
$ny_trips[$keys[$x]] = $station->ITEMS->ITEM[$keys[$x]];
}
for($i=0;$i < count($station->ITEMS->ITEM);$i++){
$ny_trips[$i] = $station->ITEMS->ITEM[$i];
}
Related
I am learning PHP. I am using for loop like below in one of my php function.
$numbers = $data["data"];
for ($i = 0;$i < count($numbers);$i++) {
$w->send($numbers[$i]);
}
I want check that if its last number, I need sleep some second and want call one other function. I do not know how can I do it. can anyone please suggest me what should I do for it?
Thanks
$numbers = $data["data"];
for ($i = 0,$c=count($numbers);$i < $c;$i++) {
$w->send($numbers[$i]);
if($i==$c-1){
sleep(60);
//call your function here;
}
}
You can simply do, what you want to do, after the loop:
$numbers = $data["data"];
foreach ($numbers as $number) {
$w->send($number);
}
$w->send($otherNumber);
sleep($forSomeSeconds);
I also changed the for loop to a foreach loop after the comment made by Elementary.
I use the array_rand PHP function with an array. I use it with a data fixture function wich load a set of data in a loop like this:
$random_values = array();
for ($i = 0; $i < 20; $i++) {
$random_values[] = array_rand(["1","2","3","4","5"]);
}
My result is quite always "1" in the $random_values array, the native
PHP function seems not really random, Is there another stuff to do to
improve the randomization of my algorithm ?
Notice I already know there is an official documentation here, http://php.net/manual/fr/function.array-rand.php.
How's it going? So, with array_rand, it actually returns a random key within an array. Your current code does not put the random key value into the array you want to randomize. ie echo $random_value[$random_key]... See example below, hope this helps
$random_values = array("1","2","3","4","5");
for ($i = 0; $i < 20; $i++) {
$key = array_rand($random_values);
echo $random_values[$key] . "\n";
}
I have this problem where I can't get the value from the array in the for loop but I can access it in the while loop.
I can't seem to find a answer online, so help would be much appreciated.
while ($pos = strpos($logTxt, $char, $pos))
{
$t++;
$pos += strlen($char);
$positions[$t] = $pos;
}
for($i = 0; $i < sizeof($positions); $i++)
{
$beginLine = $lastEndLine;
$endLine = $positions[2];
$textToEcho = substr($logTxt,$beginLine,$endLine);
$lastEndLine = $endLine;
}
I think that this could be pretty easily fixed by using a foreach loop instead of a for loop, because it is an array.
foreach($positions as $position) {
$beginLine = $lastEndLine;
$endLine = $position;
$textToEcho = substr($logTxt,$beginLine,$endLine);
$lastEndLine = $endLine;
}
If you want to use a for loop still, I believe your problem is you are only referencing the 3rd position of the array (Key 2, as arrays start at 0), not what the loop is pointing to. You could fix it by doing this
for($i = 0; $i < sizeof($positions); $i++)
{
$beginLine = $lastEndLine;
$endLine = $positions[$i];
$textToEcho = substr($logTxt,$beginLine,$endLine);
$lastEndLine = $endLine;
}
Your $endLine always has third element from array, because of $positions[2]. Try changing it to $positions[$i]
You base problem is using constant index in $positions[2]. But your 1st line in for loop $beginLine = $lastEndLine; will always fail because $lastEndLine is not defined yet. You can use smth like
// beginLine // endLine
$textToEcho = substr($logTxt, $positions[$i-1], $positions[$i]);
of course you need $positions[-1] set to 0 before your first loop or smth like this (it's not clear what's happening before)
UPD I've tried your code and concluded
it will not work at all if $char is the first occurence in $logTxt
it does the nearly the same as explode() function
I'm noob in PHP programming and for my surprise I found it difficult to create an array using loop and to input in it values using arithmetic progression with +4 difference.I spent over an hour and tried a lot of code,searched so many examples.Below is my code that work(maybe) but not properly.
<?php
$array = [];
for($x=0;$x<10;$x++){
for($i=0;$i<100;$i+=4){
$array[] = $i;
}
break;
}
var_dump($array);
?>
I must have no more than 10(0-9 key) values,but because of $i the loop continues to 96 up to 24 keys.Maybe it's stupid question but I've totally blocked.
Is that what you want ?
<?php
$array = [];
for($x=0;$x<10;$x++){
$array[] = $x*4;
}
var_dump($array);
?>
Or maybe simpler
$array = range(0,36,4);
Doc for range : http://php.net/manual/fr/function.range.php
Then perhaps you have been overthinking this. You just need one loop, and can simply scale your key by 4:
foreach (range(0, 10) as $x) {
$array[] = 4 * $x;
}
Which will just add 0 for key 0, and 4 for key 1, and so on.
Note that for larger ranges, you should keep the classic for of course. It's more readable/obvious for math thingys anyway.
Use this:-
for ($x = 0; $x < 10; $x++) {
$array[$x] = $x * 4;
}
echo '<pre>';
print_r($array);
I think you must read basic of array here is a link that is useful for you link
I am trying to use a for loop where it looks through an array and tries to make sure the same element is not used twice. For example, if $r or the random variable is assigned the number "3", my final array list will find the value associated with wordList[3] and add it. When the loop runs again, I don't want $r to use 3 again. Example output: 122234, where I would want something along the lines of 132456. Thanks in advance for the help.
for($i = 0; $i < $numWords; $i++){
$r = rand(0, $numWords);
$arrayTrack[$i] == $r;
$wordList[$r] = $finalArray[$i];
for($j = 0; $j <= $i; $j++){
if($arrayTrack[$j] == $r){
# Not sure what to do here. If $r is 9 once, I do not want it to be 9 again.
# I wrote this so that $r will never repeat itself
break;
}
}
Edited for clarity.
Pretty sure you are over complicating things. Try this, using array_rand():
$final_array = array();
$rand_keys = array_rand($wordList, $numWords);
foreach ($rand_keys as $key) {
$final_array[] = $wordList[$key];
}
If $numWords is 9, this will give you 9 random, unique elements from $wordList.
See demo
$range = range(0, $numWords - 1); // may be without -1, it depends..
shuffle($range);
for($i = 0; $i < $numWords; $i++) {
$r = array_pop($range);
$wordList[$r] = $finalArray[$i];
}
I do not know why you want it.. may be it is easier to shuffle($finalArray);??
So ideally "abcdefghi" in some random order.
$letters = str_split('abcdefghi');
shuffle($letters);
var_dump($letters);
ps: if you have hardcoded array $wordList and you want to take first $n elements of it and shuffle then (if this is not an associative array and you do not care about the keys)
$newArray = array_slice($wordList, 0, $n);
shuffle($newArray);
var_dump($newArray);
You can try array_rand and unset
For example:
$array = array('one','two','free','four','five');
$count = count($array);
for($i=0;$i<$count;$i++)
{
$b = array_rand($array);
echo $array[$b].'<br />';
unset($array[$b]);
}
after you have brought the data in the array, you purify and simultaneously removing the memory array
Ok... I have NO idea why you are trying to use so many variables with this.
I certainly, have no clue what you were using $arrayTrack for.
There is a very good chance I am mis-understanding all of this though.
<?php
$numWords=10;
$wordList=array('a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z');
$finalArray=array();
for ($i=0; $i<$numWords; $i++) {
start:
$r=rand(0,$numWords);
$wordChoice=$wordList[$r];
foreach ($finalArray as $word) {
if ($word==$wordChoice) goto start;
}
$finalArray[]=$wordChoice;
}
echo "Result: ".implode(',',$finalArray)."\n";