Learn PHP Variables

Learn about PHP variables and the string and number data types.

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Key Concepts

Review core concepts you need to learn to master this subject

Parsing Variables within PHP Strings

Reassignment of PHP Variables

Concatenating Strings in PHP

Appending a String in PHP

PHP Strings

PHP copying variables

PHP String Escape Sequences

PHP Evaluation Order during Assignment

Parsing Variables within PHP Strings

$my_var = "cat";

echo "There is one $my_var on the mat";

/* If there were three cats, then you can type: */
echo "There are three {$my_var}s on the mat ";
/* The curly braces help to avoid confusion between the variable name and the letter s, so PHP does not consider the variable name as my_vars */

In PHP, variables can be parsed within strings specified with double quotes (").

This means that within the string, the computer will replace an occurence of a variable with that variable’s value.

When additional valid identifier characters (ie. characters that could be included in a variable name) are intended to appear adjacent to the variable’s value, the variable name can be wrapped in curly braces {}, thus avoiding confusion as to the variable’s name.

PHP Strings and Variables

Lesson 1 of 2

1
Strings
In everyday conversation, we use the word data to refer to any sort of information. This info…
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2
Escape Sequences
We use quotation marks to indicate the start and end of a string. The quotation marks tell the computer that we want everything inside them to be treated as a single piece of data. But how do we in…
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3
String Concatenation
It can be useful to combine two strings together. This process is called string concatenation, and we can use the concatenation operator (.) to do this. An operator is a character that perfor…
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4
Variables
Let’s say I have a really long string in my program, and I’m going to need to use it multiple times. Do I have to type the string out every time I need to use it? The answer is “no”. Variables are …
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5
Creating Variables
Let’s look at an example of creating a variable: $my_name = “Aisle Nevertell”; In the code above, we’re actually doing two things with a single statement: we’re declaring a new variable by givi…
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6
Using Variables
Once we’ve declared a variable and assigned a value to it, we can use it as many times as we want. We refer to a variable by using the dollar sign followed by the variable’s name. $favorite_food …
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7
Variable Parsing
In the last exercise, we saw how concatenating a number of strings and string variables got annoying. There’s an easier way! PHP strings allow us to place variables directly into double quoted st…
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8
Variable Reassignment
The word variable comes from the latin variāre which means “to make changeable.” This is an apt name because the value assigned to a variable can change. ![gif of reassignment](https://content.co…
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9
Concatenating Assignment Operator
We can assign and reassign variables to the values that result from operations: $full_name = “Aisle” . “ Nevertell”; echo $full_name; // Prints: Aisle Nevertell During assignment, the computer wi…
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10
Assign by Reference
When we create a variable assigned to another variable, the computer finds a new space in memory which it associates with the left operand, and it stores a copy of the right operand’s value there. …
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11
Review
Awesome work! We’ve covered a lot of material in this lesson, so let’s review: - Strings are collections of text that the computer treats as a single piece of data. - A string can be any length an…
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