Please consider this silly example:
if (1..3) { "true" } The above produces the output true.
My question: How does the if statement handle a case like this where multiple values are output by the conditional? Is the "true" output the result of the "3" (the last case)? Or is some other logic at work? Thanks.
The above produces the output true, as expected.
Why do you expect it to output "true"?
How does the if statement handle a case like this where multiple values are output by the conditional?
The conditional does not "output" any values. It always evaluates to "true" or "false". The question remaining is, why does it evaluate to true (or false).
The code
if (1..3) { "true" } is equal to
if (@(1,2,3)) { "true" } is equal to
$array = @(1,2,3) if ($array) { "true" } behaves as
if ($array.Length -gt 0) { "true" } So not individual elements are tested, but rather if the array contains any elements.
For example, the following will not print "true":
if (@()) { "true" } Update If the array contains only one value, it looks (I coudn't find any normative documentation on that), as if the array is treated as a scalar value using the one element inside.
So
if (@(0)) if (@(0.0)) if (@(1)) if (@(-1)) if (,$null)) if (,"false")) is treated as
if (0) --> false if (0.0) --> false if (1) --> true if (-1) --> true if ($null) --> false if ("false") --> true The observed behavior is explained (to some extent) in this blog post. Basically, if an expression evaluates to 0 it's interpreted as false, otherwise as true. Examples:
0 => False 1 => True "0" => True (because it's a string of length 1) "" => False (because it's a string of length 0) @() => False @(0) => False (this one's a little surprising) @(0,1) => True @("0") => True 1..3 results in an array with 3 items
PS> (1..3).GetType() IsPublic IsSerial Name BaseType -------- -------- ---- -------- True True Object[] System.Array PS> (1..3).Length 3 If there is at least one item in the array the if considers it true
PS> if (@()) { "true" } else { "false" } false PS> if (@(1)) { "true" } else { "false" } true PS> if (@(1,2)) { "true" } else { "false" } true