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Browse questions with relevant PHP tags
1,467,403 questions
2769
votes
27
answers
2.2m
views
How can I prevent SQL injection in PHP?
If user input is inserted without modification into an SQL query, then the application becomes vulnerable to SQL injection, like in the following example:
$unsafe_variable = $_POST['user_input'];
...
2651
votes
36
answers
6.8m
views
How do I check if a string contains a specific word?
Consider:
$a = 'How are you?';
if ($a contains 'are')
echo 'true';
Suppose I have the code above, what is the correct way to write the statement if ($a contains 'are')?
5131
votes
24
answers
848k
views
Reference Guide: What does this symbol mean in PHP? (PHP Syntax)
What is this?
This is a collection of questions that come up now and then about syntax in PHP. This is also a Community Wiki, so everyone is invited to participate in maintaining this list.
This ...
2842
votes
31
answers
2.1m
views
How do I get a YouTube video thumbnail from the YouTube API?
If I have a YouTube video URL, is there any way to use PHP and cURL to get the associated thumbnail from the YouTube API?
- 48.6k
3106
votes
26
answers
3.8m
views
Deleting an element from an array in PHP
Is there an easy way to delete an element from an array using PHP, such that foreach ($array) no longer includes that element?
I thought that setting it to null would do it, but apparently it does ...
- 68.7k
2323
votes
32
answers
481k
views
How do you parse and process HTML/XML in PHP?
How can one parse HTML/XML and extract information from it?
1704
votes
37
answers
1.0m
views
str_starts_with and str_ends_with functions in PHP
How can I write two functions that would take a string and return if it starts with the specified character/string or ends with it?
For example:
$str = '|apples}';
echo startsWith($str, '|'); //...
- 268k
1028
votes
62
answers
1.9m
views
PHP random string generator
I'm trying to create a randomized string in PHP, and I get absolutely no output with this:
<?php
function RandomString()
{
$characters = '...
- 10.8k
2043
votes
27
answers
3.8m
views
How do I get PHP errors to display?
I have checked my PHP ini file (php.ini) and display_errors is set and also error reporting is E_ALL. I have restarted my Apache webserver.
I have even put these lines at the top of my script, and it ...
- 58k
2239
votes
24
answers
849k
views
When should I use 'self' over '$this'?
In PHP 5, what is the difference between using self and $this?
When is each appropriate?
- 52.7k
1447
votes
39
answers
2.3m
views
How to get the client IP address in PHP
How can I get the client IP address using PHP?
I want to keep record of the user who logged into my website through his/her IP address.
- 14.7k
1352
votes
39
answers
2.2m
views
Get the first element of an array
I have an array:
array( 4 => 'apple', 7 => 'orange', 13 => 'plum' )
I would like to get the first element of this array. Expected result: string apple
One requirement: it cannot be ...
- 152k
1600
votes
35
answers
4.0m
views
How do I make a redirect in PHP?
Is it possible to redirect a user to a different page through the use of PHP?
Say the user goes to www.example.com/page.php and I want to redirect them to www.example.com/index.php, how would I do so ...
- 19.1k
1322
votes
40
answers
686k
views
Enumerations on PHP
I know that PHP doesn't yet have native Enumerations. But I have become accustomed to them from the Java world. I would love to use enums as a way to give predefined values which IDEs' auto-completion ...
- 67.8k
1094
votes
47
answers
3.3m
views
How do I get the current date and time in PHP?
Which PHP function can return the current date/time?
Mike
2736
votes
14
answers
262k
views
Why shouldn't I use mysql_* functions in PHP?
What are the technical reasons for why one shouldn't use mysql_* functions? (e.g. mysql_query(), mysql_connect() or mysql_real_escape_string())?
Why should I use something else even if they work on ...
- 175k
1725
votes
30
answers
961k
views
How Can I add HTML And CSS Into PDF [closed]
I have an HTML (not XHTML) document that renders fine in Firefox 3 and IE 7. It uses fairly basic CSS to style it and renders fine in HTML.
I'm now after a way of converting it to PDF. I have tried:...
1290
votes
39
answers
285k
views
Reference - What does this error mean in PHP?
What is this?
This is a number of answers about warnings, errors, and notices you might encounter while programming PHP and have no clue how to fix them. This is also a Community Wiki, so everyone is ...
1449
votes
30
answers
720k
views
Difference between require, include, require_once and include_once?
In PHP:
When should I use require vs. include?
When should I use require_once vs. include_once?
- 40.3k
938
votes
47
answers
355k
views
How to check if PHP array is associative or sequential?
PHP treats all arrays as associative, so there aren't any built in functions. Can anyone recommend a fairly efficient way to check if an array "is a list" (contains only numeric keys ...
873
votes
41
answers
1.4m
views
How do I get the query builder to output its raw SQL query as a string?
Given the following code:
DB::table('users')->get();
I want to get the raw SQL query string that the database query builder above will generate. In this example, it would be SELECT * FROM users.
...
- 11.7k
1373
votes
29
answers
2.2m
views
"Notice: Undefined variable", "Notice: Undefined index", "Warning: Undefined array key", and "Notice: Undefined offset" using PHP
I'm running a PHP script and continue to receive errors like:
Notice: Undefined variable: my_variable_name in C:\wamp\www\mypath\index.php on line 10
Notice: Undefined index: my_index C:\wamp\www\...
1022
votes
32
answers
1.9m
views
Convert a PHP object to an associative array
I'm integrating an API to my website which works with data stored in objects while my code is written using arrays.
I'd like a quick-and-dirty function to convert an object to an array.
- 37.4k
965
votes
36
answers
3.1m
views
How do I convert a string to a number in PHP?
I want to convert these types of values, '3', '2.34', '0.234343', etc. to a number. In JavaScript we can use Number(), but is there any similar method available in PHP?
Input Output
'2' ...
- 14.7k
719
votes
48
answers
531k
views
dyld: Library not loaded: /usr/local/opt/icu4c/lib/libicui18n.62.dylib error running php after installing node with brew on Mac
I installed node using homebrew (Mojave), afterwards php stoped working and if I try to run php -v I get this error:
php -v
dyld: Library not loaded: /usr/local/opt/icu4c/lib/libicui18n.62.dylib
...
- 8,931
975
votes
27
answers
4.1m
views
Get the full URL in PHP
I use this code to get the full URL:
$actual_link = 'http://'.$_SERVER['HTTP_HOST'].$_SERVER['PHP_SELF'];
The problem is that I use some masks in my .htaccess, so what we see in the URL is not always ...
- 45.8k
1071
votes
27
answers
1.4m
views
Remove empty array elements
Some elements in my array are empty strings from users. $linksArray still has empty elements after the following:
foreach($linksArray as $link)
{
if($link == '')
{
unset($link);
}
}...
- 11.2k
1189
votes
21
answers
1.3m
views
PHP array delete by value (not key)
I have a PHP array like so:
$messages = [312, 401, 1599, 3, ...];
Given that the values in the array are unique, how can I delete the element with a given value (without knowing its key)?
- 13.2k
883
votes
33
answers
873k
views
How can I get a file's extension in PHP?
This is a question you can read everywhere on the web with various answers:
$ext = end(explode('.', $filename));
$ext = substr(strrchr($filename, '.'), 1);
$ext = substr($filename, strrpos($filename, '...
- 598k
809
votes
36
answers
1.2m
views
Finding the number of days between two dates
How to find number of days between two dates using PHP?
- 15.7k
1423
votes
18
answers
1.2m
views
Sort a 2d array by a column value
How can I sort this array by the value of the "order" key?
Even though the values are currently sequential, they will not always be.
Array
(
[0] => Array
(
[...
- 27.8k
812
votes
38
answers
2.3m
views
Fatal Error: Allowed Memory Size of 134217728 Bytes Exhausted
I have a bunch of client point of sale (POS) systems that periodically send new sales data to one centralized database, which stores the data into one big database for report generation.
The client ...
- 8,161
1007
votes
31
answers
777k
views
mysql_fetch_array()/mysql_fetch_assoc()/mysql_fetch_row()/mysql_num_rows etc... expects parameter 1 to be resource
I am trying to select data from a MySQL table, but I get one of the following error messages:
mysql_fetch_array() expects parameter 1 to be resource, boolean given
This is my code:
$username = $...
- 25.1k
830
votes
33
answers
1.1m
views
How to calculate the difference between two dates using PHP?
I have two dates of the form:
Start Date: 2007-03-24
End Date: 2009-06-26
Now I need to find the difference between these two in the following form:
2 years, 3 months and 2 days
How can I do this ...
gnanesh
597
votes
40
answers
479k
views
phpmyadmin - count(): Parameter must be an array or an object that implements Countable [closed]
I've uploaded the backup to a table, opening the table I see this:
Warning in ./libraries/sql.lib.php#601
count(): Parameter must be an array or an object that implements Countable
Backtrace
./...
- 5,916
1160
votes
20
answers
1.6m
views
Returning JSON from a PHP Script
I want to return JSON from a PHP script.
Do I just echo the result? Do I have to set the Content-Type header?
- 11.8k
656
votes
41
answers
740k
views
How can I get useful error messages in PHP?
Quite often I will try and run a PHP script and just get a blank screen back. No error message; just an empty screen. The cause might have been a simple syntax error (wrong bracket, missing semicolon),...
- 8,720
830
votes
16
answers
2.1m
views
How to fix "Headers already sent" error in PHP
When running my script, I am getting several errors like this:
Warning: Cannot modify header information - headers already sent by (output started at /some/file.php:12) in /some/file.php on line 23
...
1145
votes
16
answers
642k
views
What is the difference between public, private, and protected?
When and why should I use public, private, and protected functions and variables inside a class? What is the difference between them?
Examples:
// Public
public $variable;
public function ...
- 58.4k
1159
votes
18
answers
1.6m
views
How do I use PHP to get the current year?
I want to put a copyright notice in the footer of a web site, but I think it's incredibly tacky for the year to be outdated.
How would I make the year update automatically with PHP
- 11.7k
1170
votes
18
answers
681k
views
808
votes
27
answers
890k
views
Pretty-Printing JSON with PHP
I'm building a PHP script that feeds JSON data to another script. My script builds data into a large associative array, and then outputs the data using json_encode. Here is an example script:
$data = ...
- 21.4k
1184
votes
18
answers
1.2m
views
How do I expire a PHP session after 30 minutes?
I need to keep a session alive for 30 minutes and then destroy it.
- 34.4k
1286
votes
17
answers
703k
views
How can I sanitize user input with PHP?
Is there a catchall function somewhere that works well for sanitizing user input for SQL injection and XSS attacks, while still allowing certain types of HTML tags?
- 23.7k
802
votes
24
answers
1.9m
views
Show a number to two decimal places
What's the correct way to round a PHP string to two decimal places?
$number = "520"; // It's a string from a database
$formatted_number = round_to_2dp($number);
echo $formatted_number;
The output ...
- 73.1k
827
votes
25
answers
661k
views
Get first key in a (possibly) associative array?
What's the best way to determine the first key in a possibly associative array? My first thought it to just foreach the array and then immediately breaking it, like this:
foreach ($an_array as $key =&...
- 26.1k
1371
votes
14
answers
219k
views
UTF-8 all the way through
I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.
Where ...
- 22.6k
1103
votes
15
answers
1.3m
views
Where can I find php.ini?
Today I needed to install the IBM DB2 library. I went through all the steps up to make install, and I found ibm_db2.so in $PHP_HOME/lib/extensions/somecomplicatedname/ibm_db2.so.
The great catch is ...
- 24.7k
2286
votes
7
answers
462k
views
How does PHP 'foreach' actually work?
Let me prefix this by saying that I know what foreach is, does and how to use it. This question concerns how it works under the bonnet, and I don't want any answers along the lines of "this is how you ...
- 88.7k
780
votes
21
answers
903k
views
Create a folder if it doesn't already exist
I've run into a few cases with WordPress installs with Bluehost where I've encountered errors with my WordPress theme because the uploads folder wp-content/uploads was not present.
Apparently the ...
- 40.3k
MUGWANEZA M...
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