Concatenate array of strings, and prepending another string with F#

Question

I have a string array lines, for example

lines = [| "hello"; "world" |]

I'd like to make a string line that concatenates the elements in lines with "code=" string prepended. For example, I need to get the string code="helloworld" from the lines array.

I could get the concatenated string with this code

let concatenatedLine = lines |> String.concat ""

And I tested this code to prepend "code=" string as follows, but I got error FS0001: The type 'string' is not compatible with the type 'seq<string>' error.

let concatenatedLine = "code=" + lines |> String.concat ""

What's wrong with this?

Stephen Swensen · Accepted Answer · 2011-05-31 15:52:04Z

5

+ binds stronger than |>, so you need to add some parentheses:

let concatenatedLine = "code=" + (lines |> String.concat "")

Otherwise the compiler parses the expression like:

let concatenatedLine = (("code=" + lines) |> (String.concat ""))
                         ^^^^^^^^^^^^^^^
                         error FS0001

edited May 31, 2011 at 15:52

answered May 31, 2011 at 15:46

Stephen Swensen

22.3k9 gold badges84 silver badges140 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

manojlds · Accepted Answer · 2011-05-31 15:48:29Z

2

I think you want to try the following ( forward piping operator has lower precedence)

let concatenatedLine = "code=" + (lines |> String.concat "" )

answered May 31, 2011 at 15:48

manojlds

303k66 gold badges483 silver badges426 bronze badges

Collectives™ on Stack Overflow

Concatenate array of strings, and prepending another string with F#

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related