问题
I want to concatenate a few links with a pipe. But all links are surrounded by an if-statement.
Example:
- if condition1
= link_to link1
- if condition2
= link_to link2
- if condition3
= link_to link3
If condition 1 and 2 are true, the result should be
link1 | link2
Any hints how to do this?
回答1:
I would use smth like that for that purpose:
= [[l1, c1], [l2, c2], [l3, c3]].map{ |l, c| link_to(l) if c }.compact.join('|')
or
= [(link_to(l1) if c1),(link_to(l2) if c2),(link_to(l3) if c3)].compact.join('|')
The last one is a bit clumsy but it's a matter of taste. Both works perfectly for filtering out unnecessary links and joining the rest of them with |.
Though, if your conditions are non-trivial and you have quite a few of them it'd be better to move that logic outside of view into controller or some helper (depending on the situation).
And if you have some common method for testing whether you should display link or not, let's say show?(link) helper, then things become a bit nicer and you can do it like that:
= [l1, l2, l3, l4].map{ |l| link_to(l) if show?(l) }.compact.join('|')
or like that:
= [l1, l2, l3, l4].select{ |l| show?(l) }.map{ |l| link_to(l) }.join('|')
来源：https://stackoverflow.com/questions/8639847/concatenate-link-to-with-pipe