How to implement for loop logic [closed] - php

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Is there a simple logic to implement for loop, demending on delimeter?
if $a>b for($i=a; $i>b; $i--)
else for($i=a; $i<b; $i++)
But I need it to be done in one loop I cant do something like
$start = $a<$b? $a : $b;
Because I need loop to always start with $a and go toward $b, maybe there another way?Can i have reason for downvoting? And what is unclear in my question, peoples if you dont understand question refrain from touching it.


Hope this helps
$inc = $a < $b ? 1: -1;
for ($i = $a; $i != $b; $i += $inc) {
/* some code here */
}
Explanation:
First step is estimation of the increment meaning whether to increment or decrement $a to reach $b.
Obviously if $a < $b then increment needed or else decrement. $i += $inc is the generic statement that adds +1 or -1. Adding +1 is increment and adding -1 is decrement.
Ultimately the loop exit condition is $i != $b, hoping this condition will be met atleast once in the increment/decrement.


Your question contains some logical error. Although syntax is correct.
if $a<b for($i=a; $i>b; $i--)
Here, $a is smaller than b and in for loop you give condition $i>b which will never meet because $i and $a are already smaller than b. So, this loop will not run even for a single time. This is also same for else because here also loop will not execute for a single time.
Is that you want..?

Related

How to use a sign plus in a PHP variable and get result? [closed]

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I want to store a plus sign (or any other sign) in a PHP variable and make arithmetic operation.
I tried to store sign plus in variable $c. But PHP it's not accepting it.
$a = 3;
$b = 5;
$с = "+";
But when I echo it,
echo $a. $c. $b;
it gives me the result 35.
I tried enothoer one way, but it doesn't work:
if ($c === "+"){
echo $a + $b;}
else {
echo $a - $b;}
The result is -2.
How get result $a + $b?

You're using a combination of the Cyrillic and latin letter c in your code.
If I paste your code on this site to show each unicode char, the first c is an \u0441 (Cyrillic), how ever, the c inside the if shows 0x63 (latin), so PHP is unable to match those and trows:
PHP Notice: Undefined variable: c
Fixed:
<?php
$a = 3;
$b = 5;
$c = "+";
if ($c === "+"){
echo $a + $b;}
else {
echo $a - $b;}
Try it online!

PHP: Is there a difference between use of ++ or +=1 [closed]

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When using increment on variables in Javascript, lint says that x += 1 is preferred over x ++.
But what about in PHP?
Is there any difference between the += and ++ or does it just not really matter?

Well whatever you might say about conventions, try running the following...
$i = 1; $s = 's';
$i++; $s++;
echo $i.'<br>'.$s.'<br>';
$i = 1; $s = 's';
$i += 1; $s += 1;
echo $i.'<br>'.$s.'<br>';
the output is somewhat unexpected...
2
t
2
1
so I would say it could matter very much which is chosen!

x += 1 is rather equivalent to ++x.
All those expressions (x += 1, x++ and ++x) increment the value of num by one, but the value of x++ is the value x had before it got incremented.

Logic to divide any integer number into same five parts [closed]

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Want to divide random integer number into equal five parts. And insert those values into array. Can any one tell me the logic for that.
Eg. I have 15 as my number. After dividing. It should generate the array as below.
$myArray = array('3','6','9','12','15');
Thanks in advance.

function getParts($number, $parts)
{
return array_map('round', array_slice(range(0, $number, $number / $parts), 1));
}
print_r(getParts(15, 5));
Explanation: range() generates the array of values starting with 0, ending when it reaches $number and using the step $number/$parts. It will get $parts+1 floating point numbers. array_slice() removes the first item (which is always 0). array_map() applies the function round() to each element to get the nearest integer.

Divide and create a loop to fill the array...
$total = 15;
$divide = 5;
$base = $total / $divide;
$arr = array();
for($i = 1; $i <= $divide; $i++) {
$arr[] = round($i * $base);
}

Define array with variable index [closed]

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My code:
$rank_content = file('https://www.championsofregnum.com/index.php?l=1&ref=gmg&sec=42&world=2');
$line_count = 0;
//initializing only the first few keys because of no reason (the latter ones aren't in use yet)
$rankNameArr = array(0=>42,1=>42,2=>42,3=>42,4=>42,5=>42,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72);
$rankRlmpArr = array(0=>42,1=>42,2=>42,3=>42,4=>42,5=>42,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72);
while ($line = array_shift($rank_content)) { // retrieving line after line of the website, does work indeed
$line_count += 1;
if(strpos($line, "Warrior #") || strpos($line, "Archer #") || strpos($line, "Mage #"))
{
$rankNameArr[$line_count] = $line_count + 1; // HERE nothing happens
$rankRlmpArr[$line_count] = $line_count + 2; // nothing happens here, too
}
}
Why does
echo $rankNameArr[2];
echo $rankRlmpArr[2];
give me the value 42 instead of the correct value? If I replace $line_count with a real number, the script works properly.
My intention is to store the value $line_count + 1 into $rankNameArr at position $line_count. Not very complicated actually
EDIT -------------
Forget everything above, please. I finally reduced the script to the actual problem:
$arr = array(0=>42,1=>42,2=>42,3=>42,4=>42,5=>42,6=>42);
$counter=0;
for($i=0;$i<7;$i++) {
$arr[$counter]=$i;
}
echo $arr[5];
This sadly echoes 42. I have no idea how to have $arr[$counter] store the actual value of $i.

I have no idea how to have $arr[$counter] store the actual value of $i.
$counter is set to 0, so $arr[$counter] is the same as saying $arr[0]. If you echo $arr[0] you'll see that it is being changed while the rest are left alone, which means your code is working.
However if you want $counter to increment also, you just need to tell it to do so:
$arr = array(0=>42,1=>42,2=>42,3=>42,4=>42,5=>42,6=>42);
$counter=0;
for($i=0;$i<7;$i++) {
$counter++;
$arr[$counter]=$i;
}
echo $arr[5];

Where could I possibly be messing up in a for loop? [closed]

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Here is what I am doing (php)
<?php
for($i = 0; $i <= 30; $i+2)
{
echo $i;
}
?>
It drives me nuts,coz it does not work [prints nothing, browser keeps trying to load]. But if I change $i+2 to $i++, it works, and if I change it to $i+1, that does not work either.
I am out of my wits. What is going wrong?

It drives me nuts,coz it does not work [prints nothing, browser keeps trying to load]. But if I change $i+2 to $i++, it works, and if I change it to $i+1, that does not work either.
$i++ is equivalent to $i = $i + 1, note the assignment operator =, it isn't present here $i + 2 adds but doesn't update ...
since $i is never updated, you have an infinite loop, where the script will probably reach the allowable time for processing and terminate.
http://php.net/manual/en/function.set-time-limit.php
Set the number of seconds a script is allowed to run. If this is reached, the script returns a fatal error. The default limit is 30 seconds or, if it exists, the max_execution_time value defined in the php.ini.

You need to change $i+2 to $i = $i + 2 or $i += 2.
$i++ means $i += 1.
for($i = 0; $i <= 30; $i += 2)
{
echo $i;
}

You need to provide some increment /decrement value to the for loop after each iteration.
$i+2 does not change the value of i. So what is happening in your case is the for loop finds the same value of i for each successive iteration.Consequently the termination condition is never met.The for loop is hence stuck in an infinite loop.
Change: $i+1 to $i=$i+1 or $i+=1.
$i++ actually means $i=$i+1.

You have to change to $i=$i+2, because $i++ is equal to $i=$i+1.

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