Today we will be taking a quick look at Single vs Double Quotes In PHP. This is going to be a very brief tutorial. Most people (myself inclusive) misuse this quotes. Now that I understand where and when they are being used, I decided to share it with you guys.
The Single Quotes (”)
The single quotes will not interpret the value of the variables enclosed in them. The single quotes will output the string as they are without any interpretation. Let demonstrate this with example:

//let declare a variable and assign value to it
$variable = "Tutorialslodge";
echo 'This lesson is from $variable';

When the code snippets above is executed, it will out put: This lesson is from $variable. This is to show that the single quotes will display whatever it contains as it is.
The Double Quotes (“”)
The Double Quotes unlike the Single Quotes will not only output values but also interpret any variables it contains. Let use the same example from above to demonstrate Double Quotes:

//let declare a variable and assign value to it
$variable = "Tutorialslodge";
echo "This lesson is from $variable";

When this code is executed, the PHP HyperText Preprocessor will parse the $variable in the double quotes and replace it with the value which that variable holds. So our code will output: This lesson is from Tutorialslodge.
So you now know when and where to use each of the quotes. Remember if you want your variables to be interpreted, use Double Quotes, hence use Single Quotes.
I hope this tutorial is helpful. Kindly drop your comments, questions, suggestions and views in the box below.
source: http://tutorialslodge.com/single-vs-double-quotes-php/

This is a good one. I have never noticed this

blenyo11:
This is a good one. I have never noticed this

it happens...thats why no one is an island of knowledge

Very wrong. Try this out
[quote]//let declare a variable and assign value
to it
$variable = "Tutorialslodge";
echo 'This lesson is from '.$variable.' ';[\quote]

tobyemmanuel:
Very wrong. Try this out

HEy , What he said is true. Moreover the example you sited is very different from what meakhel illustrated in his first post.

NOTE: Am not an expert. I believe we are all here to learn !

tobyemmanuel:
Very wrong. Try this out

your code is way different from mine. you didn't quote $variable, you only concatenated it to the quoted string.

// a workaround
$wrk = 'work it around';
echo 'we can{$wrk} for single quotes'; //we can work it around for single quotes