I don’t do functional programming as a rule. Maybe I should. As it is I merely flirt with it now and then.
Here is one pattern that I have definitely settled on, and that I think everyone should use. Functional string building. When you finish reading this there should be no excuse for ugly old imperative concatenation loops.
Instead we create our concatenated mega-string using the nice functional approach of mapping our input list inside a multi-line template literal.
JavaScript [try it online]
let list = ["Apple", "Banana", "Cherry"];
let freshness = fruit => `I like a nice fresh ${fruit}`;
let poem = `Fruity Freshness
----------------
${list.map(freshness).join('\n')}
I'm full`;
PowerShell [try it online]
$list = "Apple", "Banana", "Cherry"
function freshness ([Parameter(ValueFromPipeline)]$fruit) {Process{ "I like a nice fresh $fruit" }}
$poem = @"
Fruity Freshness
----------------
$(($list | freshness) -join "`n")
I'm full
"@
C# [try it online]
using System.Linq;
var list = new System.Collections.Generic.List<string> {"Apple", "Banana", "Cherry"};
Func<string,string> freshness = (fruit) => $"I like a nice fresh {fruit}";
var poem = $"Fruity Freshness
----------------
{String.Join("\n", list.Select(freshness).ToList())}
I'm full";
All return the same result:
Fruity Freshness ---------------- I like a nice fresh Apple I like a nice fresh Banana I like a nice fresh Cherry I'm full
I used a function statement in PowerShell because piping to it is more natural. You can instead assign a scriptblock to a variable and make it more analogous to the other examples. Notice that you now have to &execute the $variable in the pipeline.
PowerShell modifications [try it online]
$freshness = {Param([Parameter(ValueFromPipeline)]$fruit) Process{ "I like a nice fresh $fruit" }}
$list | &$freshness
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