php for nested loop and if not working - php

Question

I'm new to php and I try to make a simple program. to show a result for ex : if the array only contains a the $result will be "a" , if b the $result will be "b", if a & b then "ab" etc. in this case the array contains a, b, and c and for some reason when I run it only shows "c".
here's my code :
$a[0] = "b";
$a[1] = "a";
$a[2] = "c";
for ($j=0; $j<sizeof($a); $j++) {
for ($k=0; $k<sizeof($a); $k++) {
for ($l=0; $l<sizeof($a); $l++) {
if ($a[$j] == "a"){
$result="a";
}
elseif ($a[$j] == "b") {
$result="b";
}
elseif ($a[$j] == "c") {
$result="c";
}
elseif ($a[$j] == "a" and $a[$k] == "b") {
$result="ab";
}
elseif ($a[$j] == "c" and $a[$k] == "b" and $a[$l] == "a") {
$result="abc";
}
elseif ($a[$j] == "b" and $a[$k] == "c") {
$result="bc";
}
}
}
}
echo ($result);
thanks in advance

Answer 1

Use only one loop and three flags. Try something like this
$a[0] = "b";
$a[1] = "a";
$a[2] = "c";
$hasA = false;
$hasB = false;
$hasC = false;
for ($j=0; $j<sizeof($a); $j++) {
if ($a[$j] == "a"){
$hasA = true;
}
elseif ($a[$j] == "b"){
$hasB = true;
}
elseif ($a[$j] == "c"){
$hasC = true;
}
}
if ($hasA) echo 'a';
if ($hasB) echo 'b';
if ($hasC) echo 'c';

Answer 2

First of all those loops aren't really necessary.
Use php switches.
switch($value){
case "a":
// Actions here
case "b":
// Actions here
}
What you are doing in those for loops is keep overriding $result with a new value.
In the end it shows the last letter it found.
Aside from the fact, what purpose this code has. Try to look for a php debugger I would recommend using Xdebug.
A debugger helps a programmer detect problems by stepping into the code line by line and showing the state of every variable.
A good tutorial and development environnement tutorial is found here

Answer 3

Let's take a different approach:
$array="asdasd";
$check=$arry[0];
$all_the_same=true;
for($i=1; $i<count($array); $i++){
if(array[$i] !== $check){
$all_the_same=false;
break;
}
}
What I've done is to check all letters in the array to see if they're all the same, and set $all_the_same to false if they're not. To find out if the array has the letter you want:
if($check==="a")
echo "has 'a'";
or perhaps the more civilized switch / case statement.
The problem with your code is that you run three loops over the same data. $j changes very slowly (every sizeof($a) squared to be precise) and it's the first thing you check so it's no surprise it always shows "c".

Answer 4

$a[0] = "b";
$a[1] = "a";
$a[2] = "c";
$result = '';
foreach($a as $value) {
if($value == 'a')
$result .= 'a';
if($value == 'b')
$result .= 'b';
if($value == 'c')
$result .= 'c';
}
echo $result;
Here is a smoother version of what you tried to do!

Answer 5

sort($array);
implode( array_unique( $array ) );
As #GarethL had mentioned

Answer 6

here is a simpler way to achieve this:
$a = array('a', 'b', 'c');
$result = '';
if(in_array('a', $a)){
$result .= 'a';
}
if(in_array('b', $a)){
$result .= 'b';
}
if(in_array('c', $a)){
$result .= 'c';
}
echo $result;

Answer 7

For the intention of the question, may meet this simple code
<?php
$a[0] = "b";
$a[1] = "a";
$a[2] = "c";
$result = implode($a);
echo $result;