How do I concatenate strings and variables in PowerShell?

Question

Suppose I have the following snippet:

$assoc = New-Object PSObject -Property @{
    Id = 42
    Name = "Slim Shady"
    Owner = "Eminem"
}

Write-Host $assoc.Id + "  -  "  + $assoc.Name + "  -  " + $assoc.Owner

I'd expect this snippet to show:

42 - Slim Shady - Eminem

But instead it shows:

42 + - + Slim Shady + - + Eminem

Which makes me think the + operator isn't appropriate for concatenating strings and variables.

How should you approach this with PowerShell?

Unrestraint

Your code works if all elements are strings and you enclose the expression in parentheses: Write-host ($assoc.Id.ToString() + " - " + $assoc.Name + " - " + $assoc.Owner) here $assoc.Id is an Int32 so we have to use its string representation. Otherwise PS tries to perform an arithmetic addition instead of concatenation. – Lillylillywhite

Given the number of views I thought it was appropriate to repair the text of this question, even though my edits changed the contents quite a bit. I've tried to keep the terminology/wording and spirit of the question intact, while improving it enough so that it may be reopened. – Ries

Answer 1

Write-Host "$($assoc.Id) - $($assoc.Name) - $($assoc.Owner)"

See the Windows PowerShell Language Specification Version 3.0, p25, sub-expressions expansion.

Carthusian

This technique works with Write-Output et al too, so it is probably the most useful one to have in your toolbox. – Banquet

Why the $($name) vs just $name? Is this just defensive in the same way as in bash using ${name}? – Married

This isn't technically concatenation. – Roguish

@DannyStaple the question has been edited so much that the answer doesn't make sense anymore. In the slim shady example, yes "... $name ..." will work all the same, but in the original question for which this answer addresses, the question is how to access object properties. so if $name.id -eq 42 then "... $name.id ..." would not work like you want because it would render like ... @{id=42}.id ... instead of the desired ... 42 ... For that, use the answer's method "... $($name.id) ...". I'm bookmarking question to edit later. – Sporran

This doesn't work for distributing strings across multiple lines. Instead use ( $string1, $string2, $string3 ) -join "" or ($string1 + $string2 + $string3). With these methods, you can have whitespace (spaces, tabs, and newlines) between the strings, but be sure that (1) each string has a comma/space after it on the same line, (2) you use the back-tick character ` at the end of any empty lines between your code, and (3) if you use -join, the end bracket and the -join operator must be on the same line – Assuming

you sure it's on page 34? Literal page or page no in the down-right corner? I checked both places and didn't find it... – Squarerigger

@JingHe That answer is from 2013 ... I guess the document has changed quite a lot since then. – Carthusian

Answer 2

There is a difference between single and double quotes. (I am using PowerShell 4).

You can do this (as Benjamin said):

$name = 'Slim Shady'
Write-Host 'My name is'$name
-> My name is Slim Shady

Or you can do this:

$name = 'Slim Shady'
Write-Host "My name is $name"
-> My name is Slim Shady

The single quotes are for literal, output the string exactly like this, please. The double quotes are for when you want some pre-processing done (such as variables, special characters, etc.)

So:

$name = "Marshall Bruce Mathers III"
Write-Host "$name"
-> Marshall Bruce Mathers III

Whereas:

$name = "Marshall Bruce Mathers III"
Write-Host '$name'
-> $name

(I find How-to: Escape characters, Delimiters and Quotes good for reference).

Spates

Works with 1.0 too. – Misology

This quote rule and demo for concatenation is applicable to 'nix shell scripting (e.g. Bash), in addition to PowerShell. The portability factor alone earns my vote. – Seaware

powershell is neat and will put a space between the string and the content of the variable in Write-Host 'My name is'$name – Leyla

@Santropedro Try it online! – Leyla

Answer 3

You can also use -join

E.g.

$var = -join("Hello", " ", "world");

Would assign "Hello world" to $var.

So to output, in one line:

Write-Host (-join("Hello", " ", "world"))

Wester

at least this one could be used in foreach – Mammary

Please add that if you are using commands as inputs, wrap the command inside $().....eg... -join($(cmd1), ",", $(cmd2)) ...took me too long to figure out as I am new to powershell – Averroism

@S.Melted why wrap inside $()? – Banebrudge

Upon further review, only () is necessary for my need. For example: -join("Timestamp: ", Get-Date) gives an error, while -join("Timestamp: ", (Get-Date)) runs fine. However, this explains when $() would be necessary. – Averroism

Write-Host -join("Hello", " ", "world") will not join as the whole join argument needs brackets including the name of the arg = join. – Leyla

Thanks, this is what I needed for something like $name = -join("✅ ", $_.Substring(2)) – Demonism

Answer 4

One way is:

Write-Host "$($assoc.Id)  -  $($assoc.Name)  -  $($assoc.Owner)"

Another one is:

Write-Host  ("{0}  -  {1}  -  {2}" -f $assoc.Id,$assoc.Name,$assoc.Owner )

Or just (but I don't like it ;) ):

Write-Host $assoc.Id  "  -  "   $assoc.Name  "  -  "  $assoc.Owner

Breeze

I don't think that last one works exactly as you'd expect. See pastebin here. Powershell will add one (even though you have two here) space to the output for the whitespace between $assoc.Id and " (et al). That is, option 1 gives you Id__-__Name__-__Owner (two spaces on each side of each -), but option 3 gives Id___-___Name___-___Owner (three spaces). – Antimere

Perhaps a more useful pastebin. $assoc.Id"###"$assoc.Name will add spaces to either side of the ###, where "$($assoc.Id)###$($assoc.Name)" won't. – Antimere

I like having placeholders in the string for the variables, like in your middle example. It's handy when you want to have characters adjacent to the variable content, for example Write-Host ("Execution took {1}h, {2}m, {3}s to complete" -f $timeSpan.Hours, $timeSpan.Minutes, $timeSpan.Seconds) – Grenoble

Answer 5

Try wrapping whatever you want to print out in parentheses:

Write-Host ($assoc.Id + "  -  "  + $assoc.Name + "  -  " + $assoc.Owner)

Your code is being interpreted as many parameters being passed to Write-Host. Wrapping it up inside parentheses will concatenate the values and then pass the resulting value as a single parameter.

Eroticism

+1, I prefer this format when using other methods like Write-Debug or Write-Verbose for including double quotes and variable values, such as Write-Debug ('Running "cmdlet" with parameter $MyVar = ' + $MyVar + " at time " + (Get-Date -DisplayHint Time)) – Tova

Yes, this is string concatenation. It does not add newlines or extra spaces. It lets you use either single or double-quoted strings. – Busoni

This trick is true concatenation and allows you to do multi-line strings, like you would in .net. Very good for doing multiline SQL statements! Why doesn't powershell do this by default!? – Indignity

Thanks a bunch for this! I was having a hard time building up the URI parameter for Invoke-WebRequest and your solution was the only one that actually worked: Invoke-WebRequest -uri ('http://mysvr/guestauth/app/rest/...'+$param1+'_'+$param2+'_something,count:10') – Proscription

I had a use case where I was already in a double-quote("") and couldn't use the "accepted" answer, because it would break my string in an upper level of the command chain. Your answer was very helpful and solved my problem. Thanks! – Halverson

Answer 6

Another option is:

$string = $assoc.ID
$string += " - "
$string += $assoc.Name
$string += " - "
$string += $assoc.Owner
Write-Host $string

The "best" method is probably the one C.B. suggested:

Write-Host "$($assoc.Id)  -  $($assoc.Name)  -  $($assoc.Owner)"

Despatch

You need to add the StringBuilder option if you're going concat-crazy. ;^) – Antimere

surely there is a way to pipe the desired properties into an external file, then deserialize them into a string of components joined with hyphens(?) – Macintyre

It's hard to imagine an aproach worse than this. Strings are immutable, so each concatenation operation in fact produces a new string, copying characters of the original one. – Timid

In response to Code Jockey Using += may produce a new string each time, but for a relatively small string adding additional small strings like this, who cares. The clarity of what is happening is most important and with PowerShell just getting the thing working is more important than anything else. – Tampere

Answer 7

While expression:

"string1" + "string2" + "string3"

will concatenate the string, you need to put a $ in front of the parenthesis to make it evaluate as a single argument when passed to a PowerShell command. Example:

Write-Host $( "string1" + "string2" + "string3" )

As a bonus, if you want it to span multiple lines, then you need to use the awkward backtick syntax at the end of the line (without any spaces or characters to the right of the backtick).

Example:

Write-Host $(`
    "The rain in "        +`
    "Spain falls mainly " +`
    "in the plains"       )`
    -ForegroundColor Yellow

(Actually, I think PowerShell is currently implemented a little bit wrong by requiring unnecessary backticks between parentheses. If Microsoft would just follow Python or Tcl parenthesis rules of allowing you to put as many newlines as you want between the starting and ending parenthesis then they would solve most of the problems that people don't like about PowerShell related to line continuation, and concatenation of strings.

I've found that you can leave the backticks off sometimes on line continuations between parenthesis, but it's really flaky and unpredictable if it will work... It's better to just add the backticks.)

Chemisette

Answer 8

You need to place the expression in parentheses to stop them being treated as different parameters to the cmdlet:

Write-Host ($assoc.Id + "  -  "  + $assoc.Name + "  -  " + $assoc.Owner)

Woothen

This is compulsory for Write-Debug – Underarm

Answer 9

(Current PowerShell version 5.1.17134.407)

This also works as of now:

$myVar = "Hello"

echo "${myVar} World"

Note: this only works with double quotes

Liveried

Answer 10

Here is another way as an alternative:

Write-Host (" {0}  -  {1}  -  {2}" -f $assoc.Id, $assoc.Name, $assoc.Owner)

Charmine

Answer 11

I just want to bring another way to do this using .NET String.Format:

$name = "Slim Shady"
Write-Host ([string]::Format("My name is {0}", $name))

Margarita

Is there any advantage of using .NET String.Format instead of old plain "{0}" -f $var? I don't see the point in using .NET code where plain PowerShell can do the job... – Whacky

@DineiRockenbach Probably not. Just wanted to bring up another example. – Margarita

Answer 12

Concatenate strings just like in the DOS days. This is a big deal for logging so here you go:

$strDate = Get-Date
$strday = "$($strDate.Year)$($strDate.Month)$($strDate.Day)"

Write-Output "$($strDate.Year)$($strDate.Month)$($strDate.Day)"
Write-Output $strday

Onestep

For dates, I think the toString option is easier: (Get-Date).toString('yyyyMMdd') – Supposed

Answer 13

From What To Do / Not to Do in PowerShell: Part 1:

$id = $assoc.Id
$name = $assoc.Name
$owner = $assoc.owner
"$id - $name - $owner"

Senter

Answer 14

These answers all seem very complicated. If you are using this in a PowerShell script you can simply do this:

$name = 'Slim Shady'
Write-Host 'My name is'$name

It will output

My name is Slim Shady

Note how a space is put between the words for you

Engadine

Answer 15

I seem to struggle with this (and many other unintuitive things) every time I use PowerShell after time away from it, so I now opt for:

[string]::Concat("There are ", $count, " items in the list")

Bowl

this returns System.Object, fyi. – Byrle

Answer 16

Personally I prefer this style:

[string]::Join(' - ', 42, 'Slim Shady', 'Eminem')

or based on any object with even different attribute types:

$assoc = [psCustomObject][ordered]@{
    Id    = 42
    Name  = 'Slim Shady'
    Owner = 'Eminem'
}
[string]::Join(' - ',$assoc.psObject.Properties.value)

which gives you this result:

42 - Slim Shady - Eminem

Footsore

Answer 17

Write-Host can concatenate like this too:

Write-Host $assoc.Id" - "$assoc.Name" - "$assoc.Owner

This is the simplest way, IMHO.

Tungstite

Answer 18

$assoc = @{
    Id = 34
    FirstName = "John"
    LastName = "Doe"
    Owner = "Wife"
}

$assocId = $assoc.Id
$assocFN = $assoc.FirstName
$assocLN = $assoc.LastName
$assocName = $assocFN, $assocLN -Join " "
$assocOwner = $assoc.Owner

$assocJoin = $assocId, $assocName, $assocOwner -join " - "
$assocJoin
#Output = 34 - John Doe - Wife

Simonette

Answer 19

If you're concatenating strings to build file paths, use the Join-Path command:

Join-Path C:\temp "MyNewFolder"

It'll automatically add the appropriate trailing / leading slashes for you, which makes things a lot easier.

Reduplication

Answer 20

As noted elsewhere, you can use join.

If you are using commands as inputs (as I was), use the following syntax:

-join($(Command1), "," , $(Command2))

This would result in the two outputs separated by a comma.

See https://mcmap.net/q/53319/-how-do-i-concatenate-strings-and-variables-in-powershell for related comment

Averroism

Answer 21

Just for the fun. You can also access the values of the PSObject directly like below:

$assoc.psobject.Properties.value -join " - "

But if you do not specify that the object should be ordered, PowerShell will display the values in a random order. So you should add the flag [ordered]:

$assoc = [pscustomobject] [ordered] @{
    Id = 42
    Name = "Slim Shady"
    Owner = "Eminem"
}

Cochlea

Answer 22

You can also get access to C#/.NET methods, and the following also works:

$string1 = "Slim Shady, "
$string2 = "The real slim shady"

$concatString = [System.String]::Concat($string1, $string2)

Output:

Slim Shady, The real slim shady

Banquette