CODEWITHSUNDEEP
powershellstring-concatenation
Ninja Cowgirl
Ninja Cowgirl

Reputation: 11261

How do I concatenate strings and variables in PowerShell?

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?

Upvotes: 992

Views: 2481908

Answers (22)

David Brabant
David Brabant

Reputation: 43559

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

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

Upvotes: 1057

Carsten
Carsten

Reputation: 2207

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

Upvotes: 7

E.V.I.L.
E.V.I.L.

Reputation: 2166

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

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

Upvotes: 8

manyways
manyways

Reputation: 4756

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"))

Upvotes: 292

S. Melted
S. Melted

Reputation: 293

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://stackoverflow.com/a/34720515/11012871 for related comment

Upvotes: 3

blayderunner123
blayderunner123

Reputation: 306

$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

Upvotes: 4

Bimo
Bimo

Reputation: 6647

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.)

Upvotes: 48

TinyRacoon
TinyRacoon

Reputation: 4903

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).

Upvotes: 392

msq
msq

Reputation: 166

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.

Upvotes: 4

R.Amersfoort
R.Amersfoort

Reputation: 85

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"
}

Upvotes: 1

Benjamin
Benjamin

Reputation: 1104

(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

Upvotes: 18

Frode F.
Frode F.

Reputation: 54971

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)"

Upvotes: 44

Dave Sexton
Dave Sexton

Reputation: 11188

Here is another way as an alternative:

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

Upvotes: 15

goric
goric

Reputation: 11905

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.

Upvotes: 106

CB.
CB.

Reputation: 60958

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

Upvotes: 159

Richard
Richard

Reputation: 109130

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)

Upvotes: 40

Ian Robertson
Ian Robertson

Reputation: 2812

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

Upvotes: 0

Mordechai
Mordechai

Reputation: 745

Write-Host can concatenate like this too: 

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

This is the simplest way, IMHO.

Upvotes: 5

Luke Puplett
Luke Puplett

Reputation: 45253

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")

Upvotes: 8

Kelly Davis
Kelly Davis

Reputation: 364

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

Upvotes: 9

Martin Brandl
Martin Brandl

Reputation: 59001

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))

Upvotes: 11

elev8ed
elev8ed

Reputation: 193

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

Upvotes: 8

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