| title | description | created |
|---|---|---|
PHP CheatSheet |
The most commonly used php concepts are given here. |
2022-10-23 |
- PHP CheatSheet for Developers
| Command | Description |
|---|---|
// Comment Message |
This is a single-line comment |
$Title = "Title" |
Defining Variables |
\n |
New Line |
\r |
It inserts a carriage return in the text at this point. |
\t |
It gives a horizontal tab space |
\v |
It gives a vertical tab space |
\\ |
It adds a backslash |
\$ |
Print the next character as a dollar, not as part of a variable |
\' |
Print the next character as a double quote, not a string closer |
\" |
Print the next character as a double quote, not a string closer |
| operator | name | syntax |
|---|---|---|
+ |
Addition | $x + $y |
- |
Subtraction | $x - $y |
* |
Multiplication | $x * $y |
/ |
Division | $x / $y |
% |
Modulus | $x % $y |
** |
Exponentiation | $x ** $y |
| operator | name | syntax |
|---|---|---|
== |
Equal | $x == $y |
=== |
Identical | $x === $y |
!= |
Not equal | $x != $y |
<> |
Not equal | $x <> $y |
!== |
Not identical | $x !== $y |
> |
Greater than | $x > $y |
< |
Less than | $x < $y |
>= |
Greater than or equal to | $x >= $y |
<= |
Less than or equal to | $x <= $y |
<=> |
Spaceship | $x <=> $y |
| operator | name | syntax |
|---|---|---|
and |
And | $x and $y |
or |
Or | $x or $y |
xor |
Xor | $x xor $y |
&& |
And | $x && $y |
| |
Or | $x | $y |
! |
Not | !$x |
| operator | name | syntax |
|---|---|---|
. |
Concatenation | $txt1 . $txt2 |
.= |
Concatenation assignment | $txt1 .= $txt2 |
| operator | name | syntax |
|---|---|---|
+ |
Union | $x + $y |
== |
Equality | $x == $y |
=== |
Identity | $x === $y |
!= |
Inequality | $x != $y |
<> |
Inequality | $x <> $y |
!== |
Non-identity | $x !== $y |
| operator | name | syntax |
|---|---|---|
?: |
Ternary | $x = expr1 ? expr2 : expr3 |
?? |
Null coalescing | $x = expr1 ?? expr2 |
| operator | name | description |
|---|---|---|
++$x |
Pre-increment | Increments $x by one |
$x++ |
Post-increment | Returns $x, then increments $x by one |
--$x |
Pre-decrement | Decrements $x by one, then returns $x |
$x-- |
Post-decrement | Returns $x, then decrements $x by one |
| keyword | description |
|---|---|
$GLOBALS |
used to access global variables from anywhere in the PHP script |
$_SERVER |
holds information about headers, paths, and script locations |
$_REQUEST |
used to collect data after submitting an HTML form |
$_POST |
used to collect form data after submitting an HTML form with method="post" |
$_GET |
used to collect form data after submitting an HTML form with method="get" |
$_FILES |
an associative array containing items uploaded via HTTP POST method |
$_ENV |
An associative array of variables passed to the current script via the environment method. |
$_COOKIE |
etrieve the value of the cookie |
$_SESSION |
A session is a way to store information (in variables) to be used across multiple pages. |
| Element/Code | Description |
|---|---|
$_SERVER['PHP_SELF'] |
Returns the filename of the currently executing script |
$_SERVER['GATEWAY_INTERFACE'] |
Returns the version of the Common Gateway Interface (CGI) the server is using |
$_SERVER['SERVER_ADDR'] |
Returns the IP address of the host server |
$_SERVER['SERVER_NAME'] |
Returns the name of the host server (such as www.w3schools.com) |
$_SERVER['SERVER_SOFTWARE'] |
Returns the server identification string (such as Apache/2.2.24) |
$_SERVER['SERVER_PROTOCOL'] |
Returns the name and revision of the information protocol (such as HTTP/1.1) |
$_SERVER['REQUEST_METHOD'] |
Returns the request method used to access the page (such as POST) |
$_SERVER['REQUEST_TIME'] |
Returns the timestamp of the start of the request (such as 1377687496) |
$_SERVER['QUERY_STRING'] |
Returns the query string if the page is accessed via a query string |
$_SERVER['HTTP_ACCEPT'] |
Returns the Accept header from the current request |
$_SERVER['HTTP_ACCEPT_CHARSET'] |
Returns the Accept_Charset header from the current request (such as utf-8,ISO-8859-1) |
$_SERVER['HTTP_HOST'] |
Returns the Host header from the current request |
$_SERVER['HTTP_REFERER'] |
Returns the complete URL of the current page (not reliable because not all user-agents support it) |
$_SERVER['HTTPS'] |
Is the script queried through a secure HTTP protocol |
$_SERVER['REMOTE_ADDR'] |
Returns the IP address from where the user is viewing the current page |
$_SERVER['REMOTE_HOST'] |
Returns the Host name from where the user is viewing the current page |
$_SERVER['REMOTE_PORT'] |
Returns the port being used on the user's machine to communicate with the web server |
$_SERVER['SCRIPT_FILENAME'] |
Returns the absolute pathname of the currently executing script |
$_SERVER['SERVER_ADMIN'] |
Returns the value given to the SERVER_ADMIN directive in the web server configuration file (if your script runs on a virtual host, it will be the value defined for that virtual host) (such as [email protected]) |
$_SERVER['SERVER_PORT'] |
Returns the port on the server machine being used by the web server for communication (such as 80) |
$_SERVER['SERVER_SIGNATURE'] |
Returns the server version and virtual host name which are added to server-generated pages |
$_SERVER['PATH_TRANSLATED'] |
Returns the file system based path to the current script |
$_SERVER['SCRIPT_NAME'] |
Returns the path of the current script |
$_SERVER['SCRIPT_URI'] |
Returns the URI of the current page |
| Function | Description |
|---|---|
count(arr) |
Returns the length of an array arr |
print_r(arr) |
Prints the arr’s contents |
array_pop(arr) |
Pops (removes) an element off the end of the array arr |
array_shift(arr) |
Shifts (removes) an element off the beginning of the array arr |
array_push(arr, el) |
Pushes (adds) one or more elements onto the end of the array arr |
array_unshift(arr, el) |
Prepends one or more elements to the beginning of the array arr |
sort(arr) |
Sorts the array arr |
array_reverse(arr) |
Returns an array with elements of arr in reverse order |
in_array(el, arr) |
Returns whether a value el exists in an array arr |
list(a, b, ...) |
Assigns variables as if they were an array |
implode(glue, pieces) |
Joins array elements (pieces) with a string (glue) |
array_rand(arr) |
Randomly selects a random entry from the array and returns the key(or keys) of the random entries |
| Function | Description |
|---|---|
isset(el) |
Will return false if el has been assigned the constant NULL, el has not been set to any value yet (undefined) el has been deleted using the unset function |
print str or echo str |
Prints str |
time() |
Returns the current time in seconds |
date(format, time) |
Converts an optional time in seconds to a date based on format |
mt_rand(min, max) |
Returns a random integer between min and max (inclusive) |
header(string) |
Sends a raw HTTP header. |
die(message) |
Ends execution and sends back optional message |
include "path" |
Includes and evaluates the specified file path such as "hidden/config.php" |
| Function | Description |
|---|---|
strlen(s) |
Returns the length of a string s |
strpos(str, substr) |
Returns the position of the first occurrence of substr in str, or FALSE if not found |
substr(s, start,len) |
Returns a substring of s starting at start and up to len characters in length. If s is less than start characters long, FALSE will be returned |
trim(s) |
Strips whitespace characters from both ends of a string s |
strtolower(s) |
Returns a lowercase version of s |
strtoupper(s) |
Returns an uppercase version of s |
explode(delimiter,s) |
Returns an array of substrings of s split by delimiter |
| Function | Description |
|---|---|
file(path, [int flags = 0]) |
Reads entire file path into an array. Optional flags parameter can be passed in such as FILE_IGNORE_NEW_LINES or FILE_SKIP_EMPTY_LINES |
file_exists(path) |
Returns whether a file or directory path exists |
file_get_contents(path) |
Reads entire file path into a string |
file_put_contents(path, data) |
Writes a string data to a file path |
scandir(path) |
Returns an array of all files and directories inside the specified path including . and .. |
glob(pattern) |
Returns an array of path names matching pattern |
basename(path) |
Given a filename path, this function will strip any leading directory from a file path and return just the filename |
| Modes | Description | pointer |
|---|---|---|
r |
Open a file for read only. | File pointer starts at the beginning of the file |
w |
Open a file for write only. | Erases the contents of the file or creates a new file if it doesn't exist. File pointer starts at the beginning of the file |
a |
Open a file for write only. | The existing data in file is preserved. File pointer starts at the end of the file. Creates a new file if the file doesn't exist |
x |
Creates a new file for write only. | Returns FALSE and an error if file already exists |
r+ |
Open a file for read/write. | File pointer starts at the beginning of the file |
w+ |
Open a file for read/write. | Erases the contents of the file or creates a new file if it doesn't exist. File pointer starts at the beginning of the file |
a+ |
Open a file for read/write. | The existing data in file is preserved. File pointer starts at the end of the file. Creates a new file if the file doesn't exist |
x+ |
Creates a new file for read/write. | Returns FALSE and an error if file already exists |
| keyword | Description |
|---|---|
setcookie(name, value) |
used to set cookie with HTTP response |
$_COOKIE |
etrieve the value of the cookie |
session_start() |
A session is started |
$_SESSION |
Session variables are set with the PHP global variable |
session_unset() and session_destroy() |
To remove all global session variables and destroy the session |
| Function | Description |
|---|---|
cal_days_in_month() |
Returns the number of days in a month for a specified year and calendar |
cal_from_jd() |
Converts a Julian Day Count into a date of a specified calendar |
cal_info() |
Returns information about a specified calendar |
cal_to_jd() |
Converts a date in a specified calendar to Julian Day Count |
easter_date() |
Returns the Unix timestamp for midnight on Easter of a specified year |
easter_days() |
Returns the number of days after March 21, that the Easter Day is in a specified year |
frenchtojd() |
Converts a French Republican date to a Julian Day Count |
gregoriantojd() |
Converts a Gregorian date to a Julian Day Count |
jddayofweek() |
Returns the day of the week |
jdmonthname() |
Returns a month name |
jdtofrench() |
Converts a Julian Day Count to a French Republican date |
jdtogregorian() |
Converts a Julian Day Count to a Gregorian date |
jdtojewish() |
Converts a Julian Day Count to a Jewish date |
jdtojulian() |
Converts a Julian Day Count to a Julian date |
jdtounix() |
Converts Julian Day Count to Unix timestamp |
jewishtojd() |
Converts a Jewish date to a Julian Day Count |
juliantojd() |
Converts a Julian date to a Julian Day Count |
unixtojd() |
Converts Unix timestamp to Julian Day Count |
| Function | Description |
|---|---|
checkdate() |
Validates a Gregorian date |
date_add() |
Adds days, months, years, hours, minutes, and seconds to a date |
date_create_from_format() |
Returns a new DateTime object formatted according to a specified format |
date_create() |
Returns a new DateTime object |
date_date_set() |
Sets a new date |
date_default_timezone_get() |
Returns the default timezone used by all date/time functions |
date_default_timezone_set() |
Sets the default timezone used by all date/time functions |
date_diff() |
Returns the difference between two dates |
date_format() |
Returns a date formatted according to a specified format |
date_get_last_errors() |
Returns the warnings/errors found in a date string |
date_interval_create_from_date_string() |
Sets up a DateInterval from the relative parts of the string |
date_interval_format() |
Formats the interval |
date_isodate_set() |
Sets the ISO date |
date_modify() |
Modifies the timestamp |
date_offset_get() |
Returns the timezone offset |
date_parse_from_format() |
Returns an associative array with detailed info about a specified date, according to a specified format |
date_parse() |
Returns an associative array with detailed info about a specified date |
date_sub() |
Subtracts days, months, years, hours, minutes, and seconds from a date |
date_sun_info() |
Returns an array containing info about sunset/sunrise and twilight begin/end, for a specified day and location |
date_sunrise() |
Returns the sunrise time for a specified day and location |
date_sunset() |
Returns the sunset time for a specified day and location |
date_time_set() |
Sets the time |
date_timestamp_get() |
Returns the Unix timestamp |
date_timestamp_set() |
Sets the date and time based on a Unix timestamp |
date_timezone_get() |
Returns the time zone of the given DateTime object |
date_timezone_set() |
Sets the time zone for the DateTime object |
date() |
Formats a local date and time |
getdate() |
Returns date/time information of a timestamp or the current local date/time |
gettimeofday() |
Returns the current time |
gmdate() |
Formats a GMT/UTC date and time |
gmmktime() |
Returns the Unix timestamp for a GMT date |
gmstrftime() |
Formats a GMT/UTC date and time according to locale settings |
idate() |
Formats a local time/date as integer |
localtime() |
Returns the local time |
microtime() |
Returns the current Unix timestamp with microseconds |
mktime() |
Returns the Unix timestamp for a date |
strftime() |
Formats a local time and/or date according to locale settings |
strptime() |
Parses a time/date generated with strftime() |
strtotime() |
Parses an English textual datetime into a Unix timestamp |
time() |
Returns the current time as a Unix timestamp |
timezone_abbreviations_list() |
Returns an associative array containing dst, offset, and the timezone name |
timezone_identifiers_list() |
Returns an indexed array with all timezone identifiers |
timezone_location_get() |
Returns location information for a specified timezone |
timezone_name_from_ abbr() |
Returns the timezone name from abbreviation |
timezone_name_get() |
Returns the name of the timezone |
timezone_offset_get() |
Returns the timezone offset from GMT |
timezone_open() |
Creates new DateTimeZone object |
timezone_transitions_get() |
Returns all transitions for the timezone |
timezone_version_get() |
Returns the version of the timezonedb |
| Function | Description |
|---|---|
filter_has_var() |
Checks whether a variable of a specified input type exist |
filter_id() |
Returns the filter ID of a specified filter name |
filter_input() |
Gets an external variable (e.g. from form input) and optionally filters it |
filter_input_array() |
Gets external variables (e.g. from form input) and optionally filters them |
filter_list() |
Returns a list of all supported filter names |
filter_var() |
Filters a variable with a specified filter |
filter_var_array() |
Gets multiple variables and filter them |
| Function | Description |
|---|---|
affected_rows() |
Returns the number of affected rows in the previous MySQL operation |
autocommit() |
Turns on or off auto-committing database modifications |
begin_transaction() |
Starts a transaction |
change_user() |
Changes the user of the specified database connection |
character_set_name() |
Returns the default character set for the database connection |
close() |
Closes a previously opened database connection |
commit() |
Commits the current transaction |
connect() |
Opens a new connection to the MySQL server |
connect_errno() |
Returns the error code from the last connection error |
connect_error() |
Returns the error description from the last connection error |
data_seek() |
Adjusts the result pointer to an arbitrary row in the result-set |
debug() |
Performs debugging operations |
dump_debug_info() |
Dumps debugging info into the log |
errno() |
Returns the last error code for the most recent function call |
error() |
Returns the last error description for the most recent function call |
error_list() |
Returns a list of errors for the most recent function call |
fetch_all() |
Fetches all result rows as an associative array, a numeric array, or both |
fetch_array() |
Fetches a result row as an associative, a numeric array, or both |
fetch_assoc() |
Fetches a result row as an associative array |
fetch_field() |
Returns the next field in the result-set, as an object |
fetch_field_direct() |
Returns meta-data for a single field in the result-set, as an object |
fetch_fields() |
Returns an array of objects that represent the fields in a result-set |
fetch_lengths() |
Returns the lengths of the columns of the current row in the result-set |
fetch_object() |
Returns the current row of a result-set, as an object |
fetch_row() |
Fetches one row from a result-set and returns it as an enumerated array |
field_count() |
Returns the number of columns for the most recent query |
field_seek() |
Sets the field cursor to the given field offset |
info() |
Returns information about the last executed query |
init() |
Initializes MySQLi and returns a resource for use with real_connect() |
insert_id() |
Returns the auto-generated id from the last query |
kill() |
Asks the server to kill a MySQL thread |
more_results() |
Checks if there are more results from a multi query |
multi_query() |
Performs one or more queries on the database |
next_result() |
Prepares the next result-set from multi_query() |
options() |
Sets extra connect options and affect behavior for a connection |
ping() |
Pings a server connection, or tries to reconnect if the connection has gone down |
poll() |
Polls connections |
prepare() |
Prepares an SQL statement for execution |
query() |
Performs a query against a database |
real_connect() |
Opens a new connection to the MySQL server |
real_escape_string() |
Escapes special characters in a string for use in an SQL statement |
real_query() |
Executes a single SQL query |
reap_async_query() |
Returns result from an async SQL query |
refresh() |
Refreshes/flushes tables or caches, or resets the replication server information |
rollback() |
Rolls back the current transaction for the database |
select_db() |
Select the default database for database queries |
set_charset() |
Sets the default client character set |
set_local_infile_default() |
Unsets user defined handler for load local infile command |
set_local_infile_handler() |
Set callback function for LOAD DATA LOCAL INFILE command |
sqlstate() |
Returns the SQLSTATE error code for the error |
ssl_set() |
Used to establish secure connections using SSL |
stat() |
Returns the current system status |
stmt_init() |
Initializes a statement and returns an object for use with stmt_prepare() |
store_result() |
Transfers a result-set from the last query |
thread_id() |
Returns the thread ID for the current connection |
thread_safe() |
Returns whether the client library is compiled as thread-safe |
use_result() |
Initiates the retrieval of a result-set from the last query executed |
warning_count() |
Returns the number of warnings from the last query in the connection |
| Function | Description |
|---|---|
preg_filter() |
Returns a string or an array with pattern matches replaced, but only if matches were found |
preg_grep() |
Returns an array consisting only of elements from the input array which matched the pattern |
preg_last_error() |
Returns an error code indicating the reason that the most recent regular expression call failed |
preg_match() |
Finds the first match of a pattern in a string |
preg_match_all() |
Finds all matches of a pattern in a string |
preg_replace() |
Returns a string where matches of a pattern (or an array of patterns) are replaced with a substring (or an array of substrings) in a given string |
preg_replace_callback() |
Given an expression and a callback, returns a string where all matches of the expression are replaced with the substring returned by the callback |
preg_replace_callback_array() |
Given an array associating expressions with callbacks, returns a string where all matches of each expression are replaced with the substring returned by the callback |
preg_split() |
Breaks a string into an array using matches of a regular expression as separators |
preg_quote() |
Escapes characters that have a special meaning in regular expressions by putting a backslash in front of them |