Modified: 01/19/2015
Variable Interpolation, or Two Types of Strings
Strings with single quotes (') are literal strings, meaning there are no special characters; every character in the string will output as itself. Strings with double quotes (") in powershell will expand variables and escape characters inside the string; this is referred to as interpolation.
The following code will expand $text in the string:
$text = "John Doe"
"Hello, my name is $text.`r`nThis is a new line."
Output:
Hello, my name is John Doe. This is a new line.
However, this code will not expand $text:
'Hello, my name is $text.`r`nThis is a new line.'Output:
Hello, my name is $text.`r`nThis is a new line.
When attempting to expand a property of an object, a key of a hashtable, or an index of an array, you must enclose the variable in a subexpression ($()).
Here are some examples:
$object = Get-Item -Path .
"Here is the name of the object: $($object.Name)"
$hashtable = @{'Key'='Value'}
"Here is the value of Key in the hashtable: $($hashtable['Key'])"
$array = @('One','Two','Three')
"Here is the second item in the array: $($array[1])"If you fail to enclose these types of references in a subexpression, you will get some unexpected results.
Variable interpolation works normally when accessing variables in PS drives like the environment variable drive. Take the following code:
"The system root is $env:SystemRoot."Output:
The system root is C:\Windows.
Nested Quotations
Strings that are wrapped in double quotes (") can have single quotes (') inside them and vice versa. If you need to have a double quote as part of a string enclosed in double quotes, you can escape the double quote. You can also put two consecutive double quotes; which has the same effect as escaping the quotes. The only way to include single quotes inside a single quoted literal string is to use double single quotes. Double single quotes inside a single quoted string will be interperitted as one single quote. This is the only non-literal interpritation, that I know of anyway, that happens inside a single quoted string.
"A `"string`" with escaped inner double quotes"
"A ""string"" with dual inner double quotes"
'A ''string'' with dual inner single quotes'Output:
A "string" with escaped inner double quotes A "string" with dual inner double quotes A 'string' with dual inner single quotes
Modified: 01/19/2015
Variable Interpolation, or Two Types of Strings
Strings with single quotes (') are literal strings, meaning there are no special characters; every character in the string will output as itself. Strings with double quotes (") in powershell will expand variables and escape characters inside the string; this is referred to as interpolation.
The following code will expand $text in the string:
$text = "John Doe"
"Hello, my name is $text.`r`nThis is a new line."Output:
Hello, my name is John Doe. This is a new line.
However, this code will not expand $text:
'Hello, my name is $text.`r`nThis is a new line.'Output:
Hello, my name is $text.`r`nThis is a new line.
When attempting to expand a property of an object, a key of a hashtable, or an index of an array, you must enclose the variable in a subexpression ($()).
Here are some examples:
$object = Get-Item -Path .
"Here is the name of the object: $($object.Name)"
$hashtable = @{'Key'='Value'}
"Here is the value of Key in the hashtable: $($hashtable['Key'])"
$array = @('One','Two','Three')
"Here is the second item in the array: $($array[1])"If you fail to enclose these types of references in a subexpression, you will get some unexpected results.
Variable interpolation works normally when accessing variables in PS drives like the environment variable drive. Take the following code:
"The system root is $env:SystemRoot."Output:
The system root is C:\Windows.
Nested Quotations
Strings that are wrapped in double quotes (") can have single quotes (') inside them and vice versa. If you need to have a double quote as part of a string enclosed in double quotes, you can escape the double quote. You can also put two consecutive double quotes; which has the same effect as escaping the quotes. The only way to include single quotes inside a single quoted literal string is to use double single quotes. Double single quotes inside a single quoted string will be interperitted as one single quote. This is the only non-literal interpritation, that I know of anyway, that happens inside a single quoted string.
"A `"string`" with escaped inner double quotes"
"A ""string"" with dual inner double quotes"
'A ''string'' with dual inner single quotes'Output:
A "string" with escaped inner double quotes A "string" with dual inner double quotes A 'string' with dual inner single quotes