According to the PHP Manual, the '=>' created key/value pairs. Also, Equal or Greater than is the opposite way: '>='. In PHP the greater or less than sign always goes first: '>=', '<='. And just as a side note, excluding the second value does not work like you think it would. Instead of only giving you the key, It actually only gives you a value: Where src/ is the directory containing all your PHP code. Then, run the commands to build and run the Docker image: $ docker build -t my-php-app . $ docker run -d --name my-running-app my-php-app. We recommend that you add a php.ini configuration file; see the "Configuration" section for details. Where src/ is the directory containing all your PHP code. Then, run the commands to build and run the Docker image: $ docker build -t my-php-app . $ docker run -d --name my-running-app my-php-app. We recommend that you add a php.ini configuration file; see the "Configuration" section for details. PHP User Defined Functions. Besides the built-in PHP functions, it is possible to create your own functions. A function is a block of statements that can be used repeatedly in a program. A function will not execute automatically when a page loads. A function will be executed by a call to the function. PHP User Defined Functions. Besides the built-in PHP functions, it is possible to create your own functions. A function is a block of statements that can be used repeatedly in a program. A function will not execute automatically when a page loads. A function will be executed by a call to the function. Aug 1, 2023 · FastCGI Process Manager (FPM) Installation. Configuration. Installation of PECL extensions. Introduction to PECL Installations. Downloading PECL extensions. Installing a PHP extension on Windows. Compiling shared PECL extensions with the pecl command. Compiling shared PECL extensions with phpize. Oct 10, 2019 · Return Values: This function returns the DateTime object after subtraction is done on success or False on failure. Below programs illustrate the DateTime::sub () function in PHP: Program 1: This program uses DateTime::sub () function to subtract 2 days from given date object. Program 2: This program uses DateTime::sub () function to subtract ... A session is started with the session_start () function. Session variables are set with the PHP global variable: $_SESSION. Now, let's create a new page called "demo_session1.php". In this page, we start a new PHP session and set some session variables: Mar 7, 2017 · Key terms¶. pip is the preferred installer program. Starting with Python 3.4, it is included by default with the Python binary installers. A virtual environment is a semi-isolated Python environment that allows packages to be installed for use by a particular application, rather than being installed system wide. A session is started with the session_start () function. Session variables are set with the PHP global variable: $_SESSION. Now, let's create a new page called "demo_session1.php". In this page, we start a new PHP session and set some session variables: Dec 31, 2022 · PyPDF2 is a free and open-source pure-python PDF library capable of splitting, merging , cropping, and transforming the pages of PDF files. It can also add custom data, viewing options, and passwords to PDF files. PyPDF2 can retrieve text and metadata from PDFs as well. Aug 1, 2023 · Here's how to run dual PHP instances with PHP 5.2 and any previous PHP on Windows 2003: 1. Right-click My Computer, go to Advanced tab, and click on Environment Variables. Add the two installations and their EXT directories to the Path variable. For example, add: c:\php;c:\php\ext;c:\TMAS\php;c:\tmas\php\ext; Aug 1, 2023 · The reason for the two different variations of "and" and "or" operators is that they operate at different precedences. (See Operator Precedence.) Aug 1, 2023 · PHP 8.3.0 RC 1 available for testing. Predefined Variables. Predefined Exceptions. Predefined Interfaces and Classes. Predefined Attributes. Supported Protocols and Wrappers. Variable and Type Related Extensions. "MyClass::myFunc () ""OtherClass::myFunc () ". A class constant, class property (static), and class function (static) can all share ... Dec 19, 2021 · Just like any other programming language, PHP also supports various types of operations like arithmetic operations (addition, subtraction, etc), logical operations (AND, OR etc), Increment/Decrement Operations, etc. Thus, PHP provides us with many operators to perform such operations on various operands or variables, or values. Dec 1, 2019 · PHP is a server-side scripting language created in 1995 by Rasmus Lerdorf. PHP is a widely-used open source general-purpose scripting language that is especially suited for web development and can be embedded into HTML. What is PHP used for? As of October 2018, PHP is used on 80% of websites whose server-side language is known. It is typically ... Mar 7, 2017 · Key terms¶. pip is the preferred installer program. Starting with Python 3.4, it is included by default with the Python binary installers. A virtual environment is a semi-isolated Python environment that allows packages to be installed for use by a particular application, rather than being installed system wide. PHP is a server scripting language, and a powerful tool for making dynamic and interactive Web pages. PHP is a widely-used, free, and efficient alternative to competitors such as Microsoft's ASP. Start learning PHP now » Easy Learning with "PHP Tryit" Aug 1, 2023 · Here's how to run dual PHP instances with PHP 5.2 and any previous PHP on Windows 2003: 1. Right-click My Computer, go to Advanced tab, and click on Environment Variables. Add the two installations and their EXT directories to the Path variable. For example, add: c:\php;c:\php\ext;c:\TMAS\php;c:\tmas\php\ext; This is an example PHP application, which is intentionally vulnerable to web attacks. It is intended to help you test Acunetix. It also helps you understand how developer errors and bad configuration may let someone break into your website. You can use it to test other tools and your manual hacking skills as well. Sep 28, 2020 · A PHP framework is a platform to create PHP web applications. PHP frameworks provide code libraries for commonly used functions, cutting down on the amount of original code you need to write. There are many good reasons for using PHP frameworks as opposed to coding from scratch. Because PHP frameworks have built-in libraries and tools, the time ... Dec 23, 2022 · The Definitive PHP 7.2, 7.3, 7.4, 8.0, and 8.1 Benchmarks (2023) The year 2021 has been highly eventful for PHP ( and Kinsta ). PHP 8.0 is already a year old, and the much-anticipated PHP 8.1 was released on November 25, 2021, bringing many exciting features. You can catch up on all the latest PHP 8.1 features in our in-depth post. Click on the URL button, Enter URL and Submit. This tool supports loading the PHP File to beautify. Click on the Upload button and select File. It beautify pure PHP framework file such as Laravel, CodeIgniter, YII, CakePHP, Symfony and many more one file at a time. PHP Source Code Beautifier Online works well on Windows, MAC, Linux, Chrome ... Dec 23, 2022 · The Definitive PHP 7.2, 7.3, 7.4, 8.0, and 8.1 Benchmarks (2023) The year 2021 has been highly eventful for PHP ( and Kinsta ). PHP 8.0 is already a year old, and the much-anticipated PHP 8.1 was released on November 25, 2021, bringing many exciting features. You can catch up on all the latest PHP 8.1 features in our in-depth post. The code editor lets you write and practice different types of computer languages. It includes PHP, but you can use it for other languages too. New languages are added all the time: Learn More If you don't know PHP, we suggest that you read our PHP Tutorial from scratch. Easy Package Management Mar 7, 2017 · Key terms¶. pip is the preferred installer program. Starting with Python 3.4, it is included by default with the Python binary installers. A virtual environment is a semi-isolated Python environment that allows packages to be installed for use by a particular application, rather than being installed system wide. Aug 23, 2011 · Getting Started Introduction A simple tutorial Language Reference Basic syntax Types Variables Constants Expressions Operators Control Structures Functions Nov 21, 2022 · Step 1: First, we need to download our desired .whl file from the official PyPi website (pypi.org), open the website and click on browse projects. Step 2: After clicking browse projects click on the Python 3 compatible projects. Step 3: After clicking Python 3 compatible projects, search for the desired package of user’s choice. Basic PHP Syntax. A PHP script can be placed anywhere in the document. The default file extension for PHP files is " .php ". A PHP file normally contains HTML tags, and some PHP scripting code. Below, we have an example of a simple PHP file, with a PHP script that uses a built-in PHP function " echo " to output the text "Hello World!" May 30, 2023 · Great if you like your tutorials to the point. 11. Learn-php.org Free Interactive PHP Tutorial. Learn-php.org free interactive PHP tutorial. The unique thing about this PHP tutorial is that it’s a set of interactive exercises that encourage you to try out coding and see if you can get the expected output. Aug 1, 2023 · Returns a string formatted according to the given format string using the given integer timestamp (Unix timestamp) or the current time if no timestamp is given. In other words, timestamp is optional and defaults to the value of time(). Aug 1, 2023 · Returns a string formatted according to the given format string using the given integer timestamp (Unix timestamp) or the current time if no timestamp is given. In other words, timestamp is optional and defaults to the value of time(). The optional timestamp parameter in the date () function specifies a timestamp. If omitted, the current date and time will be used (as in the examples above). The PHP mktime () function returns the Unix timestamp for a date. The Unix timestamp contains the number of seconds between the Unix Epoch (January 1 1970 00:00:00 GMT) and the time ... Dec 19, 2021 · Just like any other programming language, PHP also supports various types of operations like arithmetic operations (addition, subtraction, etc), logical operations (AND, OR etc), Increment/Decrement Operations, etc. Thus, PHP provides us with many operators to perform such operations on various operands or variables, or values. This is like an E_WARNING set by the programmer using the PHP function trigger_error() E_USER_NOTICE 1024; User-generated notice. This is like an E_NOTICE set by the programmer using the PHP function trigger_error() E_STRICT 2048; Run-time notices. PHP suggest changes to your code to help interoperability and compatibility of the code; E ... PHP is a server side scripting language that is embedded in HTML. It is used to manage dynamic content, databases, session tracking, even build entire e-commerce sites. It is integrated with a number of popular databases, including MySQL, PostgreSQL, Oracle, Sybase, Informix, and Microsoft SQL Server. PHP is pleasingly zippy in its execution ... A session is started with the session_start () function. Session variables are set with the PHP global variable: $_SESSION. Now, let's create a new page called "demo_session1.php". In this page, we start a new PHP session and set some session variables: PHP is a server scripting language, and a powerful tool for making dynamic and interactive Web pages. PHP is a widely-used, free, and efficient alternative to competitors such as Microsoft's ASP. Start learning PHP now » Easy Learning with "PHP Tryit" Aug 1, 2023 · The reason for the two different variations of "and" and "or" operators is that they operate at different precedences. (See Operator Precedence.) Select and Filter Data From a MySQL Database. The WHERE clause is used to filter records. The WHERE clause is used to extract only those records that fulfill a specified condition. SELECT column_name (s) FROM table_name WHERE column_name operator value. To learn more about SQL, please visit our SQL tutorial. PHP can create, open, read, write, delete, and close files on the server. PHP can collect form data. PHP can send and receive cookies. PHP can add, delete, modify data in your database. PHP can be used to control user-access. PHP can encrypt data. With PHP you are not limited to output HTML. You can output images or PDF files. Jun 9, 2023 · This PHP tutorial, whether you’re a beginner or a professional, our tutorial is designed to provide you with in-depth knowledge of the PHP scripting language. With our PHP tutorial, you’ll learn all the important topics, including control statements, functions, arrays, strings, file handling, form handling, regular expressions, date and ... Aug 1, 2023 · Strings. ¶. A string is a series of characters, where a character is the same as a byte. This means that PHP only supports a 256-character set, and hence does not offer native Unicode support. See details of the string type . Note: On 32-bit builds, a string can be as large as up to 2GB (2147483647 bytes maximum) Mar 7, 2017 · Key terms¶. pip is the preferred installer program. Starting with Python 3.4, it is included by default with the Python binary installers. A virtual environment is a semi-isolated Python environment that allows packages to be installed for use by a particular application, rather than being installed system wide. Select and Filter Data From a MySQL Database. The WHERE clause is used to filter records. The WHERE clause is used to extract only those records that fulfill a specified condition. SELECT column_name (s) FROM table_name WHERE column_name operator value. To learn more about SQL, please visit our SQL tutorial. Jun 9, 2023 · This PHP tutorial, whether you’re a beginner or a professional, our tutorial is designed to provide you with in-depth knowledge of the PHP scripting language. With our PHP tutorial, you’ll learn all the important topics, including control statements, functions, arrays, strings, file handling, form handling, regular expressions, date and ... www.php.net – PHP distribution, tutorials, newsgroups, and more. www.phpfreaks.com - PHP and MySQL tutorials, scripts, forums, and more. www.phpbuilder.com – Collection of PHP resources. Hello World If your web server supports PHP, type this example into a text file called hello.php and access it in your browser by Dec 1, 2019 · PHP is a server-side scripting language created in 1995 by Rasmus Lerdorf. PHP is a widely-used open source general-purpose scripting language that is especially suited for web development and can be embedded into HTML. What is PHP used for? As of October 2018, PHP is used on 80% of websites whose server-side language is known. It is typically ... The code editor lets you write and practice different types of computer languages. It includes PHP, but you can use it for other languages too. New languages are added all the time: Learn More If you don't know PHP, we suggest that you read our PHP Tutorial from scratch. Easy Package Management Aug 23, 2011 · Getting Started Introduction A simple tutorial Language Reference Basic syntax Types Variables Constants Expressions Operators Control Structures Functions Dec 19, 2021 · Just like any other programming language, PHP also supports various types of operations like arithmetic operations (addition, subtraction, etc), logical operations (AND, OR etc), Increment/Decrement Operations, etc. Thus, PHP provides us with many operators to perform such operations on various operands or variables, or values. Dec 1, 2019 · PHP is a server-side scripting language created in 1995 by Rasmus Lerdorf. PHP is a widely-used open source general-purpose scripting language that is especially suited for web development and can be embedded into HTML. What is PHP used for? As of October 2018, PHP is used on 80% of websites whose server-side language is known. It is typically ... # Note M1 GPU support is experimental, see Thinc issue #792 python -m venv .env source .env/bin/activate source .env/bin/activate.env\Scripts\activate python -m venv .env source .env/bin/activate source .env/bin/activate.env\Scripts\activate conda create -n venv conda activate venv pip install -U pip setuptools wheel pip install -U pip setuptools wheel pip install -U spacy conda install -c ... Jun 25, 2023 · How to Install Python PIP? Python PIP comes pre-installed on 3.4 or older versions of Python. To check whether PIP is installed or not type the below command in the terminal. pip --version. This command will tell the version of the Pip if it is already installed in the system. Checking Python PIP version. PHP can create, open, read, write, delete, and close files on the server. PHP can collect form data. PHP can send and receive cookies. PHP can add, delete, modify data in your database. PHP can be used to control user-access. PHP can encrypt data. With PHP you are not limited to output HTML. You can output images or PDF files. Feb 1, 2023 · shell. python -m pip install wget python3 -m pip install wget py -m pip install wget. Alternatively, you can install the wget module in a virtual environment: Open the root directory of your project. Press Shift and right-click in Explorer. Click on "Open PowerShell window here". Run the following commands. Mar 7, 2017 · Key terms¶. pip is the preferred installer program. Starting with Python 3.4, it is included by default with the Python binary installers. A virtual environment is a semi-isolated Python environment that allows packages to be installed for use by a particular application, rather than being installed system wide. Aug 1, 2023 · PHP 8.3.0 RC 1 available for testing. Predefined Variables. Predefined Exceptions. Predefined Interfaces and Classes. Predefined Attributes. Supported Protocols and Wrappers. Variable and Type Related Extensions. "MyClass::myFunc () ""OtherClass::myFunc () ". A class constant, class property (static), and class function (static) can all share ... Dec 19, 2021 · Just like any other programming language, PHP also supports various types of operations like arithmetic operations (addition, subtraction, etc), logical operations (AND, OR etc), Increment/Decrement Operations, etc. Thus, PHP provides us with many operators to perform such operations on various operands or variables, or values. PHP can create, open, read, write, delete, and close files on the server. PHP can collect form data. PHP can send and receive cookies. PHP can add, delete, modify data in your database. PHP can be used to control user-access. PHP can encrypt data. With PHP you are not limited to output HTML. You can output images or PDF files. Jul 17, 2023 · pip install mysql-connector-pythonCopy PIP instructions. Latest version. Released: Jul 17, 2023. Where src/ is the directory containing all your PHP code. Then, run the commands to build and run the Docker image: $ docker build -t my-php-app . $ docker run -d --name my-running-app my-php-app. We recommend that you add a php.ini configuration file; see the "Configuration" section for details. A session is started with the session_start () function. Session variables are set with the PHP global variable: $_SESSION. Now, let's create a new page called "demo_session1.php". In this page, we start a new PHP session and set some session variables: Jun 9, 2023 · This PHP tutorial, whether you’re a beginner or a professional, our tutorial is designed to provide you with in-depth knowledge of the PHP scripting language. With our PHP tutorial, you’ll learn all the important topics, including control statements, functions, arrays, strings, file handling, form handling, regular expressions, date and ... Aug 1, 2023 · <html> <head> <title>Example</title> </head> <body> <?php echo "Hi, I'm a PHP script!"; ?> </body> </html> Instead of lots of commands to output HTML (as seen in C or Perl), PHP pages contain HTML with embedded code that does "something" (in this case, output "Hi, I'm a PHP script!"). Aug 1, 2023 · Returns a string formatted according to the given format string using the given integer timestamp (Unix timestamp) or the current time if no timestamp is given. In other words, timestamp is optional and defaults to the value of time(). Aug 1, 2023 · Returns a string formatted according to the given format string using the given integer timestamp (Unix timestamp) or the current time if no timestamp is given. In other words, timestamp is optional and defaults to the value of time(). Click on the URL button, Enter URL and Submit. This tool supports loading the PHP File to beautify. Click on the Upload button and select File. It beautify pure PHP framework file such as Laravel, CodeIgniter, YII, CakePHP, Symfony and many more one file at a time. PHP Source Code Beautifier Online works well on Windows, MAC, Linux, Chrome ... Jan 22, 2009 · 15. According to the article How to Get Current Datetime (NOW) with PHP, there are two common ways to get the current date. To get current datetime (now) with PHP, you can use the date class with any PHP version, or better the datetime class with PHP >= 5.2. Various date format expressions are available here. Dec 8, 2021 · 7 Min Read. PHP (Hypertext Preprocessor) is known as a general-purpose scripting language that can be utilized to create intuitive and dynamic websites. It was among the pioneer server-side language that can be integrated into HTML, making it easier to include functionality to web pages without requiring to call external data. This is an example PHP application, which is intentionally vulnerable to web attacks. It is intended to help you test Acunetix. It also helps you understand how developer errors and bad configuration may let someone break into your website. You can use it to test other tools and your manual hacking skills as well. Click on the URL button, Enter URL and Submit. This tool supports loading the PHP File to beautify. Click on the Upload button and select File. It beautify pure PHP framework file such as Laravel, CodeIgniter, YII, CakePHP, Symfony and many more one file at a time. PHP Source Code Beautifier Online works well on Windows, MAC, Linux, Chrome ... PHP can create, open, read, write, delete, and close files on the server. PHP can collect form data. PHP can send and receive cookies. PHP can add, delete, modify data in your database. PHP can be used to control user-access. PHP can encrypt data. With PHP you are not limited to output HTML. You can output images or PDF files. Dec 19, 2021 · Just like any other programming language, PHP also supports various types of operations like arithmetic operations (addition, subtraction, etc), logical operations (AND, OR etc), Increment/Decrement Operations, etc. Thus, PHP provides us with many operators to perform such operations on various operands or variables, or values. Jul 17, 2023 · pip install mysql-connector-pythonCopy PIP instructions. Latest version. Released: Jul 17, 2023. Mar 15, 2022 · Click on the Advanced system settings link in the left column. From the System Properties window, click on the Advanced tab, and then click on the Environment Variables button at the bottom. Select the Path variable from the System Variables section, and then click on Edit. Add: c:\php to your system path. Sep 28, 2020 · A PHP framework is a platform to create PHP web applications. PHP frameworks provide code libraries for commonly used functions, cutting down on the amount of original code you need to write. There are many good reasons for using PHP frameworks as opposed to coding from scratch. Because PHP frameworks have built-in libraries and tools, the time ... Aug 1, 2023 · Variables in PHP are represented by a dollar sign followed by the name of the variable. The variable name is case-sensitive. Variable names follow the same rules as other labels in PHP. A valid variable name starts with a letter or underscore, followed by any number of letters, numbers, or underscores. Dec 31, 2022 · PyPDF2 is a free and open-source pure-python PDF library capable of splitting, merging , cropping, and transforming the pages of PDF files. It can also add custom data, viewing options, and passwords to PDF files. PyPDF2 can retrieve text and metadata from PDFs as well. PHP is a server scripting language, and a powerful tool for making dynamic and interactive Web pages. PHP is a widely-used, free, and efficient alternative to competitors such as Microsoft's ASP. Start learning PHP now » Easy Learning with "PHP Tryit" Jun 17, 2022 · PHP is a server-side scripting language designed specifically for web development. It is open-source which means it is free to download and use. It is very simple to learn and use. The files have the extension “.php”. Rasmus Lerdorf inspired the first version of PHP and participated in the later versions. It is an interpreted language and ... Dec 19, 2021 · Just like any other programming language, PHP also supports various types of operations like arithmetic operations (addition, subtraction, etc), logical operations (AND, OR etc), Increment/Decrement Operations, etc. Thus, PHP provides us with many operators to perform such operations on various operands or variables, or values. Aug 1, 2023 · The reason for the two different variations of "and" and "or" operators is that they operate at different precedences. (See Operator Precedence.) Mar 7, 2017 · Key terms¶. pip is the preferred installer program. Starting with Python 3.4, it is included by default with the Python binary installers. A virtual environment is a semi-isolated Python environment that allows packages to be installed for use by a particular application, rather than being installed system wide.
Select and Filter Data From a MySQL Database. The WHERE clause is used to filter records. The WHERE clause is used to extract only those records that fulfill a specified condition. SELECT column_name (s) FROM table_name WHERE column_name operator value. To learn more about SQL, please visit our SQL tutorial. . Osrs karil
The code editor lets you write and practice different types of computer languages. It includes PHP, but you can use it for other languages too. New languages are added all the time: Learn More If you don't know PHP, we suggest that you read our PHP Tutorial from scratch. Easy Package Management Dec 19, 2021 · Just like any other programming language, PHP also supports various types of operations like arithmetic operations (addition, subtraction, etc), logical operations (AND, OR etc), Increment/Decrement Operations, etc. Thus, PHP provides us with many operators to perform such operations on various operands or variables, or values. Mar 15, 2022 · Click on the Advanced system settings link in the left column. From the System Properties window, click on the Advanced tab, and then click on the Environment Variables button at the bottom. Select the Path variable from the System Variables section, and then click on Edit. Add: c:\php to your system path. The code editor lets you write and practice different types of computer languages. It includes PHP, but you can use it for other languages too. New languages are added all the time: Learn More If you don't know PHP, we suggest that you read our PHP Tutorial from scratch. Easy Package Management A session is started with the session_start () function. Session variables are set with the PHP global variable: $_SESSION. Now, let's create a new page called "demo_session1.php". In this page, we start a new PHP session and set some session variables: Payee Information Portal (PIP) As of July 1, 2016, email is now the default means of communication for City agencies' Invitations for Bids (IFBs), Requests for Proposals (RFPs) and notices of availability. Notifications by paper mail, fax, hand delivery or otherwise are only available upon request to the contracting agency. Agencies will use ... Nov 21, 2022 · Step 1: First, we need to download our desired .whl file from the official PyPi website (pypi.org), open the website and click on browse projects. Step 2: After clicking browse projects click on the Python 3 compatible projects. Step 3: After clicking Python 3 compatible projects, search for the desired package of user’s choice. Jun 9, 2023 · Include as much detail as possible. To qualify for PIP, you need to show that you need help with the activities on more than half the days in a year. Make it clear on the form how often you have problems with the activities. If your health changes, explain how often this happens and the effect it has on you. Note that the ; is redundant; as the answers suggest this short-tag expands to an echo with a semicolon added to the end, as per the php documents. – not-just-yeti Oct 5, 2015 at 1:25 Where src/ is the directory containing all your PHP code. Then, run the commands to build and run the Docker image: $ docker build -t my-php-app . $ docker run -d --name my-running-app my-php-app. We recommend that you add a php.ini configuration file; see the "Configuration" section for details. This is like an E_WARNING set by the programmer using the PHP function trigger_error() E_USER_NOTICE 1024; User-generated notice. This is like an E_NOTICE set by the programmer using the PHP function trigger_error() E_STRICT 2048; Run-time notices. PHP suggest changes to your code to help interoperability and compatibility of the code; E ... Click on the URL button, Enter URL and Submit. This tool supports loading the PHP File to beautify. Click on the Upload button and select File. It beautify pure PHP framework file such as Laravel, CodeIgniter, YII, CakePHP, Symfony and many more one file at a time. PHP Source Code Beautifier Online works well on Windows, MAC, Linux, Chrome ... Jan 14, 2021 · If you have permission to SSH into the remote server, use the command line to check the installed PHP version. This method is also useful for checking the PHP version installed locally. 1. Type the PHP command: php -v. 2. The php -v command works on Linux, macOS, Windows, and other supported systems. Its output contains the PHP version number ... PHP Variables. A variable can have a short name (like x and y) or a more descriptive name (age, carname, total_volume). A variable starts with the $ sign, followed by the name of the variable. A variable name must start with a letter or the underscore character. A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9 ... .