Page 2 of PHP Articles

Working with Dynamic variable names a/k/a Variable variables in PHP

Variable variables are one of my favorite things about PHP. PHP allows you to use a variable to reference another variable. This comes in exceptionally handy when you need to create variable names dynamically: $variable = 'This is my variable'; $var = 'variable'; echo $$var; Let’s say you have you […]

Get all defined variables in PHP

I’ve never actually used this function, but could definitely see using it to help profile a system and/or to help identify defined but unused variables. To obtain an array of all of the defined variables you would: $defined = get_defined_vars(); The function returns a multi-dimensional array of all of the […]

Working with JSON in PHP

JSON is one of my favorite human readable formats. It’s widely used and has great support in PHP as well as other languages. PHP allows you to easily convert variables into JSON and JSON into objects or arrays. First, let’s take a look at how we can convert an array […]

Truncate string with ellipses with PHP

We previously discussed how to calculate the length of a string in PHP and I made mention that using that function is how you would go about truncating a string if it’s over a specific length. I also said that down the road I would discuss the topic at hand, […]

Get date for Easter in PHP

All the good things about Easter aside, it’s one of those holidays that’s a pain to get the date for. This is because the date of Easter is based on the lunar cycle and Spring Equinox (March 21st). The date of Easter on a given year could fall between March […]

Serializing and unserializing variables in PHP

Serialization in PHP is the act of converting a variable into a storable value. When I say storable, I mean being able to store the result in say, a database or a flat file. This is commonly applied to arrays and objects as they are not simply text strings. Under […]

Calculate the length of a string with PHP

Calculating the length of a string is a useful feature of any language, in fact it’s one of the few pieces of functionality that has a consistently simple syntax across modern languages. You can calculate the length of a string as part of some server side user input validation or […]

How to get a server's hostname in PHP

The hostname of your server or local system is an easy way to determine which environment you are working with, either local or production. Prior to PHP 5.3 you would need to utilize the php_uname() function and with 5.3+ there is a built-in function for getting the hostname: pre-5.3 $hostname […]

How to save a remote file to disk with PHP

You may already be familiar with file_get_contents() for reading the contents of a local file but did you know that you can use it to read the contents of a remote file or site? You can then use file_put_contents() to write the file’s contents back to disk: file_put_contents('./some/local/file', file_get_contents('http://phpave.com')); Both […]

Basic HTTP Authentication with PHP

Basic HTTP Authentication is easily accomplished at the web server level (by way of .htaccess with Apache or inside your nginx configuration file) but did you know you could pull it off inside of a PHP script? You bet your butt you can! First, you will need to interrogate the […]

Life of Pi - Working with Pi in PHP

The irrational mathematical constant of Pi can be obtained a few different ways in PHP. There is a function to give you the value as well as a bunch of constants that represent Pi as well as fractions of Pi and it’s square root. Heck, you could even do it […]

How to replace a string with a string in PHP

String replacements in PHP are very simple and as per usual, can be done in a variety of different ways. First let’s take a look at the most simple form of a string replacement: str_replace('blue', 'red', 'My favorite color is blue'); The first argument is the string you want to […]

How to round numbers with PHP

Rounding numbers can be done a number of ways. You can round a float up or down to the nearest integer or you could round to a specific precision. Even then you can choose whether or not to round halves up or down and even round towards even and odd […]

Converting decimal to other number systems with PHP

It felt a bit like cheating to split this post up so I figured I would just cover all of the decimal to… functions in one post. Decimal, also known as base ten, is the numerical base we are most accustomed to. From time to time we need to convert […]

To infinity and beyond! Working with infinity in PHP

We can file this one under the “PHP functions I never knew existed and probably will never use” category. Seems that as of PHP 4.2.0 and beyond there was the inclusion of an is_finite() and an is_infinite() function. The names are pretty self explanatory and I’m sure there are some […]

Finding the smallest or largest value with PHP

Figured I would keep up the trend of talking about finding the smallest and largest values in arrays by talking about finding the smallest or largest value in a set of values. Incidentally, doing so will utilize the same min() and max() functions we used previously. Not one of my […]

Find the largest value in an array with PHP

Last week we discussed how to find the smallest value in an array so it seemed fitting to discuss how to find the largest value in an array. As we previously discussed back in the day you would have to loop through an array and compare values until you found […]

Find the lowest value in an array with PHP

Finding the lowest value of an array is a pretty common task in PHP, especially when you are dealing with things like scores or money. In the old days before PHP 4, finding the lowest value of an array meant looping through the array and comparing values until you had […]

How to convert an array to a string with PHP

Converting an array to a string is a pretty frequent task when programming. Whether you want to join some sentences into a paragraph or just smash the values into some sort of hash, you can do so very simply with PHP’s implode function. Implode takes 1 to 2 arguments. In […]

Days until Christmas in PHP

The holidays are upon us so it’s time for my obligatory holidays themed post! Keep in mind that the title may say Christmas but you could apply this same logic to any holiday or date of your choosing. $christmas = date('Y-12-25'); $today = date('Y-m-d'); echo (strtotime($christmas) - strtotime($today)) / 86400; […]

How to reverse a string with PHP

Reversing a string in most languages is a pretty trivial task. In PHP we have a dedicated strrev function to do so: $string = 'This is my awesome string!'; $reverse = strrev($string); But what if this function didn’t exist? How would you go about reversing the string? For me, I’d […]

How to generate a date range with PHP

From time to time I need to loop through a date range. One approach is to generate a start date and an end date and then add 1 day to the start date until it reaches the end date (or whatever interval you want to increment by). This works wonders […]

How to convert a string to an array with PHP

Converting a string to an array is a pretty common task when programming in PHP. If you don’t know much about PHP you could easily fall into a situation where you’re manually looping through each character in a string checking for a delimiter or keeping a counter and assembling strings […]

Sort an array in reverse order with PHP

Arrays are a great way to store / work with data. In PHP, arrays are one of the most powerful data types of available. From time to time, you need to sort an array in reverse order. Of course, PHP has you covered: $array = [ 1 => 'one', 2 […]

Pull random values from an array with PHP

Like most things, you can solve this problem with a number of different approaches. Without knowing about array_rand in PHP, you could end up doing something like this to pull a random value from an array: $array = ['one', 'two', 'three', 'four', 'five']; shuffle($array); echo $array[0]; The array is shuffled […]