Ruby - retrieve value, validate and assign value in one line

Question

tc = order.total_cost.to_f rescue nil
msg.totalCost = tc if tc

here is total_cost retrieved (order.total_cost.to_f rescue nil), validated (if tc) and assigned (msg.totalCost = tc). I wonder whether all the operations could be made in one line without having to retrieve order.total_cost twice (assume that retrieval is a heavy time consumer operation).

http://stackoverflow.com/questions/876089/who-wrote-this-programing-saying-always-code-as-if-the-guy-who-ends-up-maintai — Denis de Bernardy, Dec 25 '14 at 08:34

joelparkerhenderson · Accepted Answer · 2014-12-25T09:27:23.510

1

Yes, you can do it on one line if you must:

(tc = order.total_cost.to_f rescue nil) and (msg.totalCost = tc)

This is the same logic and may be a bit easier to comprehend:

if (tc = order.total_cost.to_f rescue nil) then (msg.totalCost = tc) end

If you're willing to use semi-colons, and you know the setter won't raise, this is better:

begin; msg.totalCost = order.total_cost.to_f; rescue; end

edited Dec 25 '14 at 09:27

answered Dec 25 '14 at 08:41

joelparkerhenderson

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Can't imagine anyone to be so determined on saving lines to allow this crime against readability :) – Sergio Tulentsev Dec 25 '14 at 09:05

Ruby - retrieve value, validate and assign value in one line

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