Skip parent if using PHP - php

Not sure if this is even possible, but the basic idea of the code is as follows:
if(isset($_POST['submit'])) {
if($_POST['field'] == 0) {
// do not process the code in the if statement
}
// code to process if the above validation criteria is not met
}
I basically want to try and keep it as simple as possible without lots of if's everywhere, just the quick validation statements at the top, and if none of those if statements are triggered, it will process the code to update the database etc.
I have tried the continue statement function with no joy, I believe that only works with loops.
Thanks!

if(isset($_POST['submit']) && $_POST['field'] != 0) {
}
As a function
function testCondition() {
return isset($_POST['submit']) &&
$_POST['field'] != 0;
}
if (testCondition()) { ... }

You could put all of this in a function and then call 'return' from the inside 'if':
if(isset($_POST['submit']) && validate_form())
{
...
}
function validate_form()
{
if($_POST['field'] == 0) {
return false;
}
if(another check that fails) {
return false;
}
...
return true;
}

To accomplish this as you originally desired, you need to use the break statement. From the PHP manual:
$arr = array('one', 'two', 'three', 'four', 'stop', 'five');
while (list(, $val) = each($arr)) {
if ($val == 'stop') {
break; /* You could also write 'break 1;' here. */
}
echo "$val<br />\n";
}
/* Using the optional argument. */
$i = 0;
while (++$i) {
switch ($i) {
case 5:
echo "At 5<br />\n";
break 1; /* Exit only the switch. */
case 10:
echo "At 10; quitting<br />\n";
break 2; /* Exit the switch and the while. */
default:
break;
}
}

Related

PHP: Is there an alternative to using multiple if-statements?

I am in the making of some code that needs to check if a users login details are correct, and I therefore need a lot of if-statements inside each other. If any of the conditions in the if-statements are not true, they should alle return the same value. Is there an easy way of doing this, instead of writing the same multiple times? I have made an example below to visualize my problem. As you can see here I write " else { return false; }" multiple time, and this is what I am wondering if you are able to do more efficiently. Maybe so I only have to write "or else return false" once.
//some code
if (/*some condition*/) {
//some code
if (/*some new condition*/) {
//some code
if (/*some new condition*/) {
//some code
} else {
return false;
}
} else {
return false;
}
} else {
return false;
}
I am having a hard time finding a good way to explain my problem, so if you have a more elegant way of explaining it, do not hesitate to edit my post. I am also not quite sure that the title is as good as it could be, so if you have any ideas to an alternativ please say so :)
Lets say you have something like that (I added No):
if ( condition1 ) {
//some code 1
if ( condition2 ) {
//some code 2
if ( condition3 ) {
//some code 3
} else {
return false;
}
} else {
return false;
}
} else {
return false;
}
Since each time a condition is false, you exit the function returning false, you can directly test if the condition is false using a negation (if the negated condition is true):
if ( !condition1 ) {
return false;
}
//some code 1
if ( !condition2 ) {
return false;
}
//some code 2
if ( !condition3 ) {
return false;
}
//some code 3
This doesn't reduce the number of if statements, but you avoid many nesting levels and the else statements.
You can also try the switch statement. For many situations it will produce cleaner code.
<?php
if ($i == 0) {
echo "i equals 0";
} elseif ($i == 1) {
echo "i equals 1";
} elseif ($i == 2) {
echo "i equals 2";
}
switch ($i) {
case 0:
echo "i equals 0";
break;
case 1:
echo "i equals 1";
break;
case 2:
echo "i equals 2";
break;
}
?>
The switch statement is also compatible with using strings:
<?php
switch ($i) {
case "apple":
echo "i is apple";
break;
case "bar":
echo "i is bar";
break;
case "cake":
echo "i is cake";
break;
}
?>
Good luck! :)

How i can use if/else/elseif statment in my case - PHP

How i can use if/else/elseif... in my case,
Because when i try those statment,
It says: syntax error, unexpected 'if' (T_IF)
I need to repeat elseif more than 1x time
$row = array();
$row[] = if($aRow['status'] == "deleted"){'code..'};
This might be what you are after. You would loop over each record in your result array you get from fetchAll(), put your if/elseif block here, then I'm assuming your doing some sort of processing and saving the value to $row array?
$row = array();
$result = $sth->fetchAll();
foreach($result as $aRow){
if($aRow['status'] == "deleted"){
//do something
$row[] = //whatever
}
elseif($aRow['status'] == "something else"){
//do something else;
$row[] = //whatever else
}
}
You have 2 ways for implementing this by PHP:
The 1st way
you can use if/else/elseif:
if ($status_var=="deleted")
{
//code .....
}
elseif ($status_var=="inserted")
{
//code .....
}
elseif ($status_var=="edited")
{
//code .....
}
esle
{
//code .....
}
The 2nd way
You can use switch/case structure:
switch ($status_var)
{
case "deleted":
//code .....
break;
case "inserted":
//code .....
break;
case "edited":
//code .....
break;
default:
//code .....
}
You can use ternary operator to assign the result:
$row = array();
$row[] = $aRow['status'] == "deleted" ? 'code..' : null;
When you need to do more things depending on status, best way would be to introduce a function for that:
function process($aRow) {
if ($aRow['status'] == "deleted") {
// do something when `deleted`
return 1;
} elseif ($aRow['status'] == "new") {
// do something when `new`
return 2;
} elseif ($aRow['status'] == "updated") {
// do something when `updated`
return 3;
} else {
// do something else
return 4;
}
}
$row = array();
$row[] = process($aRow);

Is there any possibility to break a loop while calling a function?

Let's say I have a simple code:
while(1) {
myend();
}
function myend() {
echo rand(0,10);
echo "<br>";
if(rand(0,10) < 3) break;
}
This will not work with error code 'Fatal error: Cannot break/continue 1 level on line'.
So is there any possibility to terminate the loop during a subfunctin execution?
Make the loop condition depend upon the return value of the function:
$continue = true;
while( $continue) {
$continue = myend();
}
Then, change your function to be something like:
function myend() {
echo rand(0,10);
echo "<br>";
return (rand(0,10) < 3) ? false : true;
}
There isn't. Not should there be; if your function is called somewhere where you're not in a loop, your code will stop dead. In the example above, your calling code should check the return of the function and then decide whether to stop looping itself. For example:
while(1) {
if (myend())
break;
}
function myend() {
echo rand(0,10);
echo "<br>";
return rand(0,10) < 3;
}
Use:
$cond = true;
while($cond) {
$cond = myend();
}
function myend() {
echo rand(0,10);
echo "<br>";
if(rand(0,10) < 3) return false;
}

How do you use break in php 5.4 after it lost its ability to receive variables?

The php manual states under 'Changelog for break':
5.4.0 Removed the ability to pass in variables (e.g., $num = 2; break $num;) as the numerical argument.
I have a function that copies a table with a tree structure to another table.
After copying each record, the function tests a relation to see if that record has more child records in the next "level" of the tree.
If child records are found, this same function is executed for each child record using a foreach() loop. If they also have child records, the process is repeated, etc. etc.
So the number of "branches" and "levels" in the table will determine how many foreach() loops will be executed. Since the user creates the records, I have no control over the number of "branches" and "levels" in the table.
If break cannot receive a variable any more (I cannot run "branch" and "level" counters any more) - how do you break out of ALL loops if an error occurs?
Scaled down example:
public function copyTreeModels($row, $id)
{
try
{
/* copy current record. */
$status == 'ok';
/* loop to this same function if $status == 'ok' and hasChildren */
if($status == 'ok')
{
If ($row['hasChildren'] == 'yes') // check relation
{
foreach($row['children'] as $child)
{
$this->copyTreeModels($child, $id);
}
}
}
else
{
// break;
throw new CDbException($message);
}
}
catch(CDbException $e)
{
$message .= $e->getMessage();
}
return($message);
}
Don't put try in the recursive function. You need a wrapper function around the whole thing that establishes the condition handler:
public function copyTreeModels($row, $id) {
try {
$this->copytreeModelsRecurse($row, $id);
}
catch(CDbException $e)
{
$message .= $e->getMessage();
}
return($message);
}
copyTreeModelsRecurse would then be your copyTreeModels function, but without the try/catch blocks.
The only thing I can think of is to set a variable which determines whether or not to break all.
An example (untested) is
$break_all = false;
foreach($values as $val) {
foreach($val as $val1) {
foreach($val1 as $val2) {
if($val2 == "xyz") {
$break_all = true;
}
if($break_all) break;
}
if($break_all) break;
}
if($break_all) break;
}
I'll agree with the fact it's not a pretty solution however.
Edit:
An alternative suggestion if the amount of nested loops to break; from is a variable amount is setting a counter and decrementing the break counter for each break, and only breaking if it is greater than 0:
$break_count = 0;
foreach($values as $val) {
foreach($val as $val1) {
foreach($val1 as $val2) {
if($val2 == "xyz") {
$break_count = 3;
}
if($break_count > 0) { $break_count--; break; }
}
if($break_count > 0) { $break_count--; break; }
}
if($break_count > 0) { $break_count--; break; }
}

Optimising a PHP If/Else statement

I'm attempting to optimise the following PHP If/Else statement. Could I rewrite the code to make use to case and switch, or should I leave it as it is, or what?
Code:
if(empty($_GET['id'])){
include('pages/home.php');
}elseif ($_GET['id'] === '13') {
include('pages/servicestatus.php');
}elseif(!empty($_GET['id'])){
$rawdata = fetch_article($db->real_escape_string($_GET['id']));
if(!$rawdata){
$title = "";
$meta['keywords'] = "";
$meta['description'] = "";
}else{
$title = stripslashes($rawdata['title']);
$meta['keywords'] = stripslashes($rawdata['htmlkeywords']);
$meta['description'] = stripslashes($rawdata['htmldesc']);
$subs = stripslashes($rawdata['subs']);
$pagecontent = "<article>" . stripslashes($rawdata['content']) . "</article>";
}
include("includes/header.php");
echo $pagecontent;
if(!$rawdata){
error_404();
}
}
Thanks
I hate switch statements, but its personal preference to be honest. As far as further optimization i'd suggest taking a look at some form of assembly language. It will give you some general ideas on how to make conditional statements more efficient. That is, it will give you a different out look on things.
if(!empty($_GET['id']))
{
if($_GET['id'] == '13')
{
include('pages/servicestatus.php');
}
else
{
$rawdata = fetch_article($db->real_escape_string($_GET['id']));
if (!$rawdata) {
$title = "";
$meta['keywords'] = "";
$meta['description'] = "";
} else {
$title = stripslashes($rawdata['title']);
$meta['keywords'] = stripslashes($rawdata['htmlkeywords']);
$meta['description'] = stripslashes($rawdata['htmldesc']);
$subs = stripslashes($rawdata['subs']);
$pagecontent = "<article>" . stripslashes($rawdata['content']) . "</article>";
}
include("includes/header.php");
echo $pagecontent;
if (!$rawdata) {
error_404();
}
}
}
else
{
include('pages/home.php');
}
switch would be appropriate if you had several discrete values for $_GET['id'] that you were checking for.
One suggestion I can make for the sake of readability is that
} elseif (!empty($_GET['id'])) {
only needs to be
} else {
Well i don't think it's necessary to switch to a swith
but you could change
} elseif (!empty($_GET['id'])) {
to just
}else{
You may want to look into breaking up your code into a MVC form; that would make it much easier to maintain your code. At least put the last clause into another file, probably called default.php and include it. Also, you might create an array of id => file key/value sets, lookup the id, and include the file.
if (isset($_GET['id'])) {
$pages = array(
0 => 'home.php',
13 => 'servicestatus.php'
);
if (isset($pages[$_GET['id']])) {
include('pages/' . $pages[$_GET['id']]);
} else {
include('pages/default.php');
}
}
Yes, switch is evaluate once, is efficient than if elseif,
and is easier to maintain with this given structure
switch ($_GET['id'])
{
case 13: ... break;
case 0 : ... break;
default: ... break;
}
I dont know, if you should, or should not, but here I wouldnt. The main reason is, that there is at least one statement, you can omit, and then, you will have just a if-elseif-else-Statement
if (empty($_GET['id'])) { /* code */ }
elseif ($_GET['id'] === '13') { /* code */ }
elseif (!empty($_GET['id'])) { /* code* }
is the same as
if (empty($_GET['id'])) { /* code */ }
elseif ($_GET['id'] === '13') { /* code */ }
else { /* code* }
In the block after that, the statement if(!$rawdata) is also duplicated.

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