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Browse questions with relevant PHP tags
1,466,892 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'];
...
5110
votes
25
answers
838k
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 ...
2653
votes
36
answers
6.7m
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 ($a contains 'are')?
2814
votes
31
answers
2.1m
views
How do I get a YouTube video thumbnail from the YouTube API?
If I have a YouTube video URL, is there any way to use PHP and cURL to get the associated thumbnail from the YouTube API?
- 48k
3074
votes
27
answers
3.8m
views
Deleting an element from an array in PHP
Is there an easy way to delete an element from an array using PHP, such that foreach ($array) no longer includes that element?
I thought that setting it to null would do it, but apparently it does ...
- 68.1k
2317
votes
32
answers
478k
views
How do you parse and process HTML/XML in PHP?
How can one parse HTML/XML and extract information from it?
1020
votes
70
answers
1.8m
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 = '...
- 10.7k
1700
votes
37
answers
996k
views
startsWith() and endsWith() 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, '|'); //...
- 266k
2017
votes
27
answers
3.6m
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 ...
- 57.3k
2232
votes
24
answers
839k
views
When should I use 'self' over '$this'?
In PHP 5, what is the difference between using self and $this?
When is each appropriate?
- 52.3k
1338
votes
39
answers
2.1m
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 ...
- 151k
1435
votes
38
answers
2.2m
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.
- 14.6k
1582
votes
34
answers
3.9m
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 ...
- 18.9k
929
votes
60
answers
345k
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 ...
1318
votes
40
answers
678k
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 ...
- 67.5k
2723
votes
14
answers
260k
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 ...
- 174k
1725
votes
30
answers
959k
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:...
1076
votes
45
answers
3.2m
views
How do I get the current date and time in PHP?
Which PHP function can return the current date/time?
Mike
1286
votes
39
answers
281k
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 ...
1443
votes
28
answers
707k
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?
- 39.7k
1363
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\...
855
votes
40
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.
...
- 11.5k
1012
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.
- 37.2k
949
votes
36
answers
3.0m
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' ...
- 14.5k
975
votes
27
answers
4.0m
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 ...
- 45.6k
1054
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);
}
}...
- 11.1k
692
votes
47
answers
479k
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
...
- 8,641
1175
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)?
- 13k
869
votes
32
answers
842k
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, '...
- 591k
797
votes
35
answers
1.2m
views
Finding the number of days between two dates
How to find number of days between two dates using PHP?
- 15.5k
1411
votes
17
answers
1.2m
views
How to Sort a Multi-dimensional Array by 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
(
[...
- 27.5k
796
votes
38
answers
2.2m
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 ...
- 8,001
1005
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 = $...
- 25k
824
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
477k
views
phpmyadmin - count(): Parameter must be an array or an object that implements Countable
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
./...
- 5,878
1146
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?
- 11.7k
651
votes
41
answers
716k
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),...
- 8,670
830
votes
16
answers
2.0m
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
...
1140
votes
16
answers
632k
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 ...
- 58.1k
1168
votes
18
answers
676k
views
1146
votes
18
answers
1.5m
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
- 11.6k
795
votes
27
answers
859k
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 = ...
- 21.1k
1177
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.
- 34.1k
792
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 $formatted_number;
The output ...
- 72.7k
825
votes
25
answers
657k
views
Get first key in a (possibly) associative array?
What's the best way to determine the first key in a possibly associative array? My first thought it to just foreach the array and then immediately breaking it, like this:
foreach ($an_array as $key =&...
- 25.8k
1285
votes
15
answers
690k
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
2282
votes
7
answers
459k
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 ...
- 88.4k
504
votes
35
answers
1.1m
views
How to convert an array to object in PHP?
How can I convert an array like this to an object?
[128] => Array
(
[status] => "Figure A.
Facebook's horizontal scrollbars showing up on a 1024x768 screen resolution."
...
- 32.7k
767
votes
21
answers
886k
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 ...
- 39.7k
1094
votes
14
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 ...
- 24.4k
madsongr
scored 10
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