Call function with parameters that also call functions (.Net and P

bsdz

Hi

I would like to construct a parameter dynamically as I pass it to a
function. The following example demonstrates my problem. Here is a simple
concat function.

PS> function concat([string]$a, [string]$b) { return $a + $b }
PS> concat "apples" " and bananas"
apples and bananas

Clearly, if I try something like this, powershell processes each token
separated by space. So I can see why this doesn't work.

PS> concat "apples" " and {0}" -f "bananas"
apples and {0}

However, if i try the following, it appears that Powershell cannot recognise
my .Net method as a function in it own right and treats it as a group of
strings (as expected by a command line program).

PS> concat "apples" [string]::Format(" and {0}", "bananas")
apples[string]::Format

I understand I can group tokens together with braces ({}); otherwise, I am
not sure how I can do what I need to do using Powershell v1. (I would also be
interested in how to do this in v2 if different).

Many thanks in advance

Shay Levi

To simplify the function and concat ALL passed arguments you can use:

PS 36> function concat {"$args"}
PS 37> concat apple "and banana" "and whatever"
apple and banana and whatever

# you need to enclose the format expression in ()
PS 38> concat "apples" (" and {0}" -f "bananas")
apples and bananas

PS 39> concat "apples" ([string]::Format(" and {0}", "bananas"))
apples and bananas



---
Shay Levi
$cript Fanatic
http://scriptolog.blogspot.com

> Hi
>
> I would like to construct a parameter dynamically as I pass it to a
> function. The following example demonstrates my problem. Here is a
> simple concat function.
>
PS>> function concat([string]$a, [string]$b) { return $a + $b } concat
PS>> "apples" " and bananas"
PS>>
> apples and bananas
>
> Clearly, if I try something like this, powershell processes each token
> separated by space. So I can see why this doesn't work.
>
PS>> concat "apples" " and {0}" -f "bananas"
PS>>
> apples and {0}
>
> However, if i try the following, it appears that Powershell cannot
> recognise my .Net method as a function in it own right and treats it
> as a group of strings (as expected by a command line program).
>
PS>> concat "apples" [string]::Format(" and {0}", "bananas")
PS>>
> apples[string]::Format
>
> I understand I can group tokens together with braces ({}); otherwise,
> I am not sure how I can do what I need to do using Powershell v1. (I
> would also be interested in how to do this in v2 if different).
>
> Many thanks in advance
>

Tao Ma

Hi bsdz,

Shay has already given solutions to help you get your work done.

You can type this in PowerShell and it will show how powershell process your
command parameters.
help about_Parsing

Tao Ma

"bsdz" <bsdz@discussions.microsoft.com> дÈëÏûÏ¢ÐÂÎÅ:1B3E175A-CF85-44A1-A89C-6622FBDD5B9D@microsoft.com...
> Hi
>
> I would like to construct a parameter dynamically as I pass it to a
> function. The following example demonstrates my problem. Here is a simple
> concat function.
>
> PS> function concat([string]$a, [string]$b) { return $a + $b }
> PS> concat "apples" " and bananas"
> apples and bananas
>
> Clearly, if I try something like this, powershell processes each token
> separated by space. So I can see why this doesn't work.
>
> PS> concat "apples" " and {0}" -f "bananas"
> apples and {0}
>
> However, if i try the following, it appears that Powershell cannot
> recognise
> my .Net method as a function in it own right and treats it as a group of
> strings (as expected by a command line program).
>
> PS> concat "apples" [string]::Format(" and {0}", "bananas")
> apples[string]::Format
>
> I understand I can group tokens together with braces ({}); otherwise, I am
> not sure how I can do what I need to do using Powershell v1. (I would also
> be
> interested in how to do this in v2 if different).
>
> Many thanks in advance
>