PHP数组 - 删除逗号，If else语句

I am relatively new to arrays, and struggling with the amount of information out there to solve my problem succinctly. This is as far as I have progressed.

My code:

<?php 

$imagearrdisplay = ",8,7,22,";

$displayitem = explode(",", $imagearrdisplay);

for($i = 0; $i < count($displayitem); $i++){

echo "
<div class='banner'><img src='/images/transitions/$displayitem[$i].jpg' /></div>
Count: $i = $displayitem[$i] ";

}

?>

It currently returns a result of:

<div class='banner'><img src='/images/transitions/.jpg' /></div>
Count: 0 =  
<div class='banner'><img src='/images/transitions/8.jpg' /></div>
Count: 1 = 8 
<div class='banner'><img src='/images/transitions/7.jpg' /></div>
Count: 2 = 7 
<div class='banner'><img src='/images/transitions/22.jpg' /></div>
Count: 3 = 22 
<div class='banner'><img src='/images/transitions/.jpg' /></div>
Count: 4 =  

What I would like to achieve is the following:

1. To remove the first and last comma within the imagearraydisplay when it explodes so that I do not end up with a blank image at the beginning and end.

2. Randomise the results of the array

3. Perform an if / else function to find the [0] and adjust the first result so that I can use css to style the image accordingly.

To be able to then produce an outcome that looks like:

<div class='firstbanner'><img src='/images/transitions/22.jpg' /></div>
<div class='banner'><img src='/images/transitions/7.jpg' /></div>
<div class='banner'><img src='/images/transitions/8.jpg' /></div

I know it's possible, though struggling through the maze of tutes out there. Any help would be really appreciated.

Try with:

$imagearrdisplay = trim(',8,7,22,', ',');
$displayitem = explode(',', $imagearrdisplay);
shuffle($displayitem);

To check if element is first just do:

if ( $i == 0 ) {}

Have you tried ltrim? http://php.net/manual/en/function.ltrim.php

$imagearrdisplay = ltrim(",8,7,22,", ",");

Also, you can use shuffle to randomize your array: http://php.net/manual/en/function.shuffle.php

To style the first image, you could use CSS instead.

.banner:first-child
{ 
background-color:yellow;
height:50px
width:50px
}

<div class='banner'><img src='/images/transitions/22.jpg' /></div>
<div class='banner'><img src='/images/transitions/7.jpg' /></div>
<div class='banner'><img src='/images/transitions/8.jpg' /></div>

Demo: http://jsfiddle.net/Sapphion/dBDqh/

1. preg_split can be used to split so that it drops empty pieces: $chars = preg_split('//', $str, -1, PREG_SPLIT_NO_EMPTY);

2. PHP has suffle for array randomization.

3. For this, something like $array[0] = str_replace(..) (first element, I suppose), would be enough.

1. An easy way to solve this would be to alter the string before you split it into an array, using e.g trim($imagearrdisplay, ','). But since you ask for a way to remove the first and last values have a look at array_pop() and array_shift().

2. To randomize the content in the array you can use shuffle().

3. To get the first element you can use an if-statement on the $i. if($i == 0) {

Use trim to remove , on the left and right. Use shuffle to randomize the array.

For the output initialize a $class variable to the first class, then iterate over all numbers, set the $class to the normal class after the first item:

$imagearrdisplay = ",8,7,22,";

$displayitem = explode(",", trim($imagearrdisplay, ','));

shuffle($displayitem);

$class = 'firstbanner';
foreach($displayitem as $item)
{
   $src = sprintf('/images/transitions/%d.jpg', $item);
   printf("<div class=\"%s\">
  <img src=\"%s\">
</div>
", $class, $src);
   $class = 'banner';
}

Demo

Note: If you use a recent CSS version, you can identify the first banner as well with the :first-child pseudo-class.

function trim_comma($string) {
    $string = ($string[0] == ',') ? substr($string, 1, strlen($string)) : $string;
    $string = ($string[strlen($string) - 1] == ',') ? substr($string, 0, strlen($string) - 1) : $string;
    return $string;
}

echo trim_comma(",test,");

//test

this will remove your comma at the begining and at the end.