Invoke-RestMethod and foreach loop - rest

Question

Via PowerShell I'm trying to get the last ticker data from all currency pairs via the public API of a cryptocurrency exchange.
For this I first get all markets and then I want to loop through these, but for some reason only the first currency pair is being returned.
Anyone knows what I'm missing?
$bt_baseapi_url = "https://bittrex.com/api/v1.1/"
$getmarkets = $bt_baseapi_url + "public/getmarkets"
$getticker = $bt_baseapi_url + "public/getticker"
$markets = Invoke-RestMethod -Uri $getmarkets
$marketnames = $markets.result
foreach ($marketname in $marketnames.marketname) {
$tickerurl = $getticker + "?market=" + $marketname
$ticker = Invoke-RestMethod -Uri $tickerurl
return $ticker.result.last
}

Answer 1

As Ansgar Wiechers suggests in a comment on the question, do not use return inside a foreach statement's body in an attempt to return (output) a value while continuing the loop; return would return from any enclosing function or script.
Instead, rely on PowerShell's implicit output behavior, as demonstrated in this simple example:
> foreach ($el in 1, 2, 3) { $el }
1
2
3
Simply referencing $el without assigning to a variable or piping / redirecting it elsewhere cause its value to be output.
If needed at all, use continue to prevent execution of subsequent statements in the loop body while continuing the loop overall; use break to exit the loop.
By contrast - and that may be the source of the confusion - inside the body of a ForEach-Object cmdlet call - as part of a pipeline - rather than the foreach statement, the rules change, and return indeed would only exit the iteration at hand and proceed with the next input object:
> 1, 2, 3 | ForEach-Object { return $_ }
1
2
3
Note that even in this case return $_ is just syntactic sugar for $_; return - i.e., an output generating statement followed by a control-flow statement, and simply using $_ may be enough.
Do NOT use break / continue with the ForEach-Object cmdlet, as these statements would look for an enclosing loop statement (such as foreach, do, while`) and - in the absence of one - exit the entire script.
Unfortunately, there is no direct way to exit a pipeline prematurely, - see https://github.com/PowerShell/PowerShell/issues/3821; make your voice heard there if you think this should change.