I have a feeling I'm going to get scolded for this but here is the question.
$seq_numbers = range('1', '24');
foreach($seq_numbers as $seq_number)
{
Bullet <?php echo $seq_number;?>
// (this successfully creates - Bullet 1, Bullet 2, etc. -
below is the problem.
<?php echo $db_rs['bullet_($seqnumber)'];?>
} // this one doesn't work.
I've tried
with curly brackets {}
I basically have a few columns that are named same except for number at the end (bullet_1, bullet_2, bullet_3, etc.) and want to get the results using a loop.
Your problem is, that PHP doesn't replace variables inside strings enclosed with single quotes. You need to use $db_rs["bullet_{$seq_number}"] or one of those:
<?php
foreach ($seq_numbers as $seq_number) {
$key = 'bullet_' . $seq_number;
echo $db_rs[$key];
}
Even shorter, but a little less clear:
<?php
foreach ($seq_numbers as $seq_number) {
echo $db_rs['bullet_' . $seq_number];
}
An entirely different approach would be to loop over the result array. Then you don't even need $seq_numbers. Just as an afterthought.
<?php
foreach ($db_rs as $key => $value) {
if (substr($key, 0, 7) == 'bullet_') {
echo $value;
}
}
Oh...and watch out for how you spell your variables. You are using $seq_number and $seqnumber.
<?php echo $db_rs['bullet_'.$seqnumber];?>
why not:
$db_rs['bullet_'.$seqnumber]
If not, what are your fields, and what does a var_dump of $db_rs look like?
try this...
$seq_numbers = range('1', '24');
foreach($seq_numbers as $seq_number)
{
Bullet <?php echo $seq_number;?>
// (this successfully creates - Bullet 1, Bullet 2, etc. -
below is the problem.
<?php echo $db_rs["bullet_($seqnumber)"];?>
} // now it works.
Related
Editing this question entirely, for future learners.
I initially asked if a single while function could replace the code below. I didn't realize while doesn't increment automatically like foreach, so no. Great answers below on better solutions using either array_slice() or the classic for loop.
foreach ($array as $key => $value) {
if ($key < 25) {
echo '<img src="'.$value.'/preview_image.jpg">';
}
}
You would still have to increment the key, plus the key would have to be uniform to work.
Foreach works on the set and is more resilient against gaps in the range. Iterating over a set with for example 1,2 and 4 as keys, works great with foreach.
Another method could be:
for ($i=0;$i<25;$i++) etc
This checks the end conditions straight away, but does not take gaps into account, which could lead to extra code in the for loop itself.
You can use simple for loop
like this
for($i = 0; $i < 25; $i++)
{
echo '<img src="'.$array[$i].'/preview_image.jpg">';
}
I like array_slice() solution.
Also you should use Alternative syntax for control structures for displaying HTML.
PHP: Alternative syntax for control structures - Manual
<?php
/* Logic Part */
$array = [...];
$array = array_slice($array, 0, 25);
// You MUST apply this function before echoing user inputs
// for the sake of security reasons.
function h($s)
{
return htmlspecialchars($s, ENT_QUOTES, 'UTF-8');
}
/* HTML Part */
?>
<!DOCTYPE html>
<meta charset="UTF-8">
<title>Example</title>
<div>
<?php foreach ($array as $value): ?>
<img src="<?=h($value)?>/preview_image.jpg">
<?php endforeach; ?>
</div>
You effectively want to retrieve the first 24 lines from a file.
There are many ways to do that.
This is one way:
$file = new SplFileObject($path);
$file->setFlags($file::DROP_NEW_LINE);
$head = new LimitIterator($file, 0, 24);
foreach ($head as $value) {
...
}
The benefit is that you get a plain variable to foreach over that provides the data you need. This works with the Decortator pattern and is pretty flexible.
If the file has less than 24 lines (records), the foreach will finish earlier.
Also this code would not read the whole file into memory only to provide the first 24 lines.
This is a brilliant little trick if I can get it to work - I have hundreds data columns from dozens of tables spread across a dozen data forms (they are HTML print forms) and they are all html with embedded php variables. Very normal. However the customer had a requirement to know what field went in where - a very good question.
So what did I do? I worked on a solution that allows the key'd arrays from the database to give up their column names. a brilliant move! except I need to do it via variable variables, and guess what, they DON'T work in a foreach loop.
here is the code
if ($_REQUEST['data']=="false"){
$supera = array("RowService", "RowSite", "RowCustomer", "RowEngineer"); //there can be many of these they are key'd arrays $RowService['column_name_1']; is the format
foreach($supera as $super){
foreach(${$super} as $key=>$value){
if (!is_numeric($key)){
${$super}[$key] = "<span style=\"color:pink;\">".$key."</span>";
}
}
}
}
as you can see I want a kill switch easy mechanism to cut and paste the key'd arrays that aren't to show real data any more rather they are to show (in pink) the column name, and (perhaps) the table name too. There is a lot of code already in place and this would be a brilliant option if it can be made to work
EDIT: this is the PHP error:
Warning: Invalid argument supplied for foreach()
EDIT: THE CODE ACTUALLY ALREADY WORKS: FIX IS TO test for is_array()
if(is_array(${$super})) foreach(${$super} as $key=>$value){
will work, as opposed to just
foreach(${$super} as $key=>$value){
I'm not sure what you are trying to achieve but your code (simplified) works just fine:
$a = array("asd", "qwe");
$asd = array("a" => 1, "b" => 2, "c" => 3);
$qwe = array("d" => 4, "e" => 5, "f" => 6);
foreach ($a as $item)
{
foreach ($$item as $key => $value)
{
echo $key . ": " . $value . "<br />";
}
}
Output:
a: 1
b: 2
c: 3
d: 4
e: 5
f: 6
Most likely one of your variables is empty (not an array) and that's why you receive that warning.
Personally, I find variable variables to be a really bad idea. There are a few ways around it.
For example:
$process = array(&$RowService,&$RowSite,&$RowCustomer,&$RowEngineer);
foreach($process as $p) {
foreach($p as $k=>$v) {
$p[$k] = "<span style=\"color:pink\">".$v."</span>";
}
}
Using references means you can affect the original variables.
If the above doesn't work (I'm not that great with references XD), try this:
$process = array($RowService,$RowSite,$RowCustomer,$RowEngineer);
foreach($process as $p) {
foreach($p as $k=>$v) {
$p[$k] = "<span style=\"color:pink\">".$v."</span>";
}
}
list($RowService,$RowSite,$RowCustomer,$RowEngineer) = $process;
As per my understanding of your requirement.
If you want to get table name with pink color then you just need to use below code
$supera = array("RowService", "RowSite", "RowCustomer", "RowEngineer"); //there can be many of these they are key'd arrays $RowService['column_name_1']; is the format
$super = array();
foreach($supera as $key=>$value){
if (!is_numeric($value)){
$super[$value] = "<span style=\"color:pink;\">".$value."</span>";
}
}
print_r($super);
So, guys, my problem is that i'm creating an array from a mysql column, but, when i echo the array items, it returns me nothing, i'm about this for a while and i'm not seeing a possible error, hope can get some help. Here' s my code: (I know about the mysql to mysqli, but i'm just beginning and trying the logical stuff. :))
$duracao = mysql_query(
"SELECT SUM(fim_periodo-inicio_periodo)/0.01666667 AS mysum
FROM afunda_eleva_$a"
); //THIS $duracao IS INSIDE A FOR LOOP THAT EXECUTES THE QUERY IF A CONDITION IS SATISFIED (DEPENDING ON $a and $prevNum), it is working fine!
while ($row2 = mysql_fetch_assoc($duracao))
{
$duracao_afunda_eleva[] = $row2['mysum'];
}
so, to test some possible problems, i've put:
$i2 = sizeof($duracao_afunda_eleva);
echo $i2;
echo <br>;
which returns me the right size of the array, the problem comes here, i think:
for($i1 = 0 ; $i1 < sizeof($duracao_afunda_eleva); $i1++)
{
echo $duracao_afunda_eleva[$i1] or die("couldn't echo"
. mysql_error());
echo "<br>";
}
and this returns me no value. I really would appreciate any suggestion. Thanks in advance!
Try print_r instead of echo - echo outputs (string)$variable, which in case of an array is just "array". Also, echo is a language construct and not a function, so your or die(...) is problematic, as language constructs don't have return values.
Generally it's better to not use or die(...) constructs, and handle problems correctly (using a defined return value, so cleanup code can run, for example). Also, not being able to output anything with echo would mean that your php/whatever installation is seriously gone bad, at which point you probably won't even reach that line in your code, and even then it won't have anything to do with mysql.
Since the problem is not in the variable, try to use an alias in your MySQL select:
SELECT SUM(fim_periodo-inicio_periodo)/0.01666667 as mysum
Then in your PHP, you can get $row2['mysum'];
It may not solve the problem, but it is a good start.
Personally I use:
$arr = array ( /* ... */ );
echo "<pre>";
var_dump($arr);
echo "</pre>";
In your last for-loop, you use $i++, it should be $i1++
A quick tip is not to use the sizeof function in your for loop. This gets run with each iteration of your loop and you will notice an improvement in performance if you move it outside the loop (or use a foreach loop instead). e.g.
$count = sizeof($duracao_afunda_eleva);
for($i = 0 ; $i < $count; $i++) {
echo $duracao_afunda_eleva[$i] . '<br />';
}
or
// Foreach loop example
foreach ($duracao_afunda_eleva as $key => $value) {
echo $value . '<br />';
}
or what you could also do is this one line
echo implode('<br />', $duracao_afunda_eleva);
Use this code:
for($i1 = 0 ; $i1 < sizeof($duracao_afunda_eleva); $i1++)
{
echo $duracao_afunda_eleva[$i1] or die("couldn't echo". mysql_error());
echo "<br>";
}
You increased $i instead of $i1.
Although, with arrays, it's usually easier to use a foreach loop.
This runs from the first to the last element in the array.
Like so:
foreach ($duracao_afunda_eleva as $value) {
echo $value;
}
I would also suggest removing the space in $row2 ['mysum']:
$duracao_afunda_eleva[] = $row2['mysum'];
Edit
Just noticed it now, but your fetch-statement is wrong... It has a typo in it:
while ($row2 = mysql_fetch_assoc($duracao))
Make sure it reads mysql instead of myqsl.
i am tring to put a loop to echo a number inside an echo ;
and i tried as bellow :
$array = array();
$result = mysql_query("SHOW TABLES FROM `st_db_1`");
while($row = mysql_fetch_row($result) ){
$result_tb = mysql_query("SELECT id FROM $row[0] LIMIT 1");
$row_tb=mysql_fetch_array($result_tb);
$array[] = $row[0];
$array2[] = $row_tb[0];
//checking for availbility of result_tb
/* if (!$result_tb) {
echo "DB Error, could not list tablesn";
echo 'MySQL Error: ' . mysql_error();
exit;
} */
}
natsort($array);
natsort($array2);
foreach ($array as $item[0] ) {
echo "<a href=show_cls_db.php?id= foreach ($array2 as $item2[0]){echo \"$item2[0]\"}>{$item[0]}<br/><a/>" ;
}
but php is not considering foreach loop inside that echo ;
please suggest me something
As mentioned by others, you cannot do loops inside a string. What you are trying to do can be achieved like this:
foreach ($array as $element) {
echo "<a href='show_cls_db.php?id=" . implode('', $array2) . "'>{$element}</a><br/>";
}
implode(...) concatenates all values of the array, with a separator, which can be an empty string too.
Notes:
I think you want <br /> outside of <a>...</a>
I don't see why you would want to used $item[0] as a temporary storage for traverser array elements (hence renamed to $element)
Just use implode instead of trying to loop the array,
foreach ($array as $item)
{
echo implode("",$array2);
}
other wise if you need to do other logic for each variable then you can do something like so:
foreach ($array as $item)
{
echo '<a href="show_details.php?';
foreach($something as $something_else)
{
echo $something_else;
}
echo '">Value</a>';
}
we would have to see the contents of the variables to understand what your trying to do.
As a wild guess I would think your array look's like:
array(
id => value
)
And as you was trying to access [0] within the value produced by the initial foreach, you might be trying to get the key and value separate, try something like this:
foreach($array as $id => $value)
{
echo $id; //This should be the index
echo $value; //This should be the value
}
foreach ($array as $item ) {
echo "<a href=\"show_cls_db.php?id=";
foreach ($array2 as $item2) { echo $item2[0]; }
echo "\">{$item[0]}<br/><a/>" ;
}
No offense but this code is... rough. Post it on codereview.stackexchange.com for some help re-factoring it. A quick tip for now would be to use PDO, and at the least, escape your inputs.
Anyway, as the answers have pointed out, you have simply echoed out a string with the "foreach" code inside it. Take it out of the string. I would probably use implode as RobertPitt suggested. Consider sorting and selecting your data from your database more efficiently by having mysql do the sorting. Don't use as $item[0] as that makes absolutely no sense at all. Name your variables clearly. Additionally, your href tag is malformed - you may not see the correct results even when you pull the foreach loop out of the echo, as your browser may render it all away. Make sure to put those quotes where they should be.
I am fairly new to PHP and programming in general... I am attempting to use a foreach loop to set some options on a page I have created. It all works except for the last section, where I am attempting to assign variables dynamically, so I can use them outside the loop.
<?PHP
$array=array(foo, bar, baz);
foreach ($array as $option) {
// I have if statements to determine what $option_req
// and $option_status end up being, they work correctly.
$option_req="Hello";
$option_status="World";
$rh='Req_';
$sh='Status_';
$$rh.$$option=$option_req;
$$sh.$$option=$option_status;
}
echo "<br>R_Foo: ".$Req_foo;
echo "<br>S_Foo: ".$Status_foo;
echo "<br>R_Bar: ".$Req_bar;
echo "<br>S_Bar: ".$Status_bar;
echo "<br>R_Baz: ".$Req_baz;
echo "<br>S_Baz: ".$Status_baz;
?>
When the loop is finished, should this now give me six variables?
$Req_foo
$Status_foo
$Req_bar
$Status_bar
$Req_baz
$Status_baz
I have played with this a bit, searches on Google seem fruitless today.
To access some array item, just access some array item.
No loops required.
$req = array("foo" => 1,
"bar" => 2,
"baz" => 3,
);
echo $req['foo'];
plain and simple
Looks like PHP doesn't like the concatenation when you're trying to do an assignment. Try doing so beforehand, like so:
<?php
$array = array('foo', 'bar', 'baz');
foreach ($array as $option)
{
$option_req="Hello";
$option_status="World";
$rh = 'Req_';
$sh = 'Status_';
$r_opt = $rh.$option;
$s_opt = $sh.$option;
$$r_opt = $option_req;
$$s_opt = $option_status;
}
echo "<br>R_Foo: ".$Req_foo;
echo "<br>S_Foo: ".$Status_foo;
echo "<br>R_Bar: ".$Req_bar;
echo "<br>S_Bar: ".$Status_bar;
echo "<br>R_Baz: ".$Req_baz;
echo "<br>S_Baz: ".$Status_baz;
As other commenters suggested, this isn't a great practice. Try storing your data in an array, rather than just cluttering up your namespace with variables.
You could (though you should not!) do:
${$rh.$option} = ...
Variable variables don't work that way. You need to have one variable containing the string.
$opt_r = $rh.$option;
$$opt_r = $option_req;
$opt_s = $sh.$option;
$$opt_s = $option_status;
Also, make sure to quote your strings:
$array=array('foo', 'bar', 'baz');
I don't suggest using variable variables, but if you want to, this is how to do it.