Quick Learn – PSMonday #3: Monday, May 16, 2016

Topic: Quotes and Strings, and Their Rules

Notice: This post is a part of the PowerShell Monday series — a group of quick and easy to read mini lessons that briefly cover beginning and intermediate PowerShell topics. As a PowerShell enthusiast, this seemed like a beneficial way to ensure those around me at work were consistently learning new things about Windows PowerShell. At some point, I decided I would share these posts here, as well. Here’s the PowerShell Monday Table of Contents.

Today, I’d like to share how to handle quotes in a string. A string is any group of alphanumeric characters to include any punctuation. Think of a string as a sentence, or a word. A string, at its smallest component, can be a single letter, a number, or as mentioned, punctuation. Yes, numbers can be strings too, although they lose their numeric properties.

It is recommended to always use single quotes to encapsulate a string, unless there’s a need for double quotes (they have a special purpose). This is considered best practice by the PowerShell community. The first example string has no internal, interruptive punctuation, such as another single quote, or apostrophe.

$String = 'A string without any quotes.'

A string without any quotes.

The next example string uses internal, double quotes. They are non-interruptive in this instance, because the string begins and ends with single quotes.

$String = 'A string with "double" quotes.'

A string with "double" quotes.

This next example includes both single and double quotes inside a string, that begins and ends with single quotes. Notice that to do this, we needed to put two side-by-side single quotes, around the word single.

$String = 'A string with ''single'' and "double" quotes.'

A string with 'single' and "double" quotes.

One of the things that you might expect to work, is escaping the single quotes instead of using side-by-side single quotes. This doesn’t work.

$String = 'This is a string with `'single`' and "double" quotes.'

At line:1 char:36
+ $String = 'This is a string with `'single`' and "double" quotes.'
+                                    ~~~~~~~~
Unexpected token 'single`'' in expression or statement.

Although I said to use single quotes to encapsulate a string, you can use double quotes if you have internal single quotes, or apostrophes, and you don’t want to use side-by-side single quotes.

$String = "I'm only using 'single' quotes in this string."

I'm only using 'single' quotes in this string.

The final reason you might use double quotes is when you want to expand, or display, the value stored in a variable(s) inside your string. You can’t do this with single quotes. Notice in the below example that we’re using side-by-side double quotes in this string.

$Word1 = 'string'
$Word2 = 'quotes'
$String = "This is a $Word1 with 'single' and ""double"" $Word2."

This is a string with 'single' and "double" quotes.

Bonus: Back to escaping, you can escape double quotes, so the example above could have been written like the example below, and therefore, not required using side-by-side double quotes. Don’t forget about apostrophes in your contractions (I’m, don’t, aren’t, etc.). You’ll need to determine a way around those as you create strings where they’re included.

$String = "This is a $Word1 with 'single' and `"double`" $Word2."

This is a string with 'single' and "double" quotes.

And with that, the third PowerShell Monday is complete. As mentioned previously, please let me know if there’s something you’d like to see discussed.

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