So I’ve got this file-checking script:
def check
ok = true
for_every_app do |app,app_info|
ok = File.exists?(app_info[:root])
end
ok
end
And it has a bug, which is that if it evaluates a good file after a
bad file, it’ll return true for the whole list.
So here’s my suggested change:
def check
ok = true
for_every_app.values.each do |app_info|
ok = File.exists?(app_info[:root]) if ok
end
ok
end
Because if we have one false value, then the whole test is
unnecessary. It’s basically like a short-circuit operator.
But I think there’s a better way to do it with map.
Something like
File.exists?(for_every_app.values.map{|x| x}
I think I’m way off, though. How do I get that right?
–
Giles B.
Blog: http://gilesbowkett.blogspot.com
Portfolio: http://www.gilesgoatboy.org
Tumblelog: http://giles.tumblr.com/
Hi –
On Thu, 23 Aug 2007, Giles B. wrote:
So I’ve got this file-checking script:
def check
ok = true
for_every_app do |app,app_info|
Do you mean for there to be an .each in there?
def check
But I think there’s a better way to do it with map.
Something like
File.exists?(for_every_app.values.map{|x| x}
I think I’m way off, though. How do I get that right?
You could do:
def check
for_every_app.all? {|app,info| File.exists?(info[:root])}
end
David
Faster, because it breaks the loop as soon as possible, and
less LOC:
def check
for_every_app.values.find do |app_info|
not File.exists?(app_info[:root])
end ? false : true
end
You may want to skip the “? false : true” part, but that breaks
the encapsulation.
gegroet,
Erik V. - http://www.erikveen.dds.nl/
On Aug 22, 2:54 pm, “Giles B.” [email protected] wrote:
And it has a bug, which is that if it evaluates a good file after a
end
I think I’m way off, though. How do I get that right?
–
Giles B.
Blog:http://gilesbowkett.blogspot.com
Portfolio:http://www.gilesgoatboy.org
Tumblelog:http://giles.tumblr.com/
How about inject?
for_every_app.inject(true) {|good,x| good = File.exists?(x) if good}
Alle mercoledì 22 agosto 2007, Erik V. ha scritto:
the encapsulation.
gegroet,
Erik V. - http://www.erikveen.dds.nl/
This is shorter, and breaks as soon as a non-existing file is found
def check
!for_every_app.values.any?{|f| !File.exist?(f)}
end
Stefano
Hi –
On Thu, 23 Aug 2007, Stefano C. wrote:
You may want to skip the “? false : true” part, but that breaks
the encapsulation.
gegroet,
Erik V. - http://www.erikveen.dds.nl/
This is shorter, and breaks as soon as a non-existing file is found
def check
!for_every_app.values.any?{|f| !File.exist?(f)}
end
You can save yourself the double negative:
for_every_app.values.all?{|f| File.exist?(f)}
And even save the creation of an intermediate array of values:
for_every_app.all?{|a,b| File.exist?(b)}
But I repeat myself 
(See my earlier post.)
David
On Aug 22, 4:34 pm, Kaldrenon [email protected] wrote:
end
for_every_app.values.each do |app_info|
Something like
Tumblelog:http://giles.tumblr.com/
How about inject?
for_every_app.inject(true) {|good,x| good = File.exists?(x) if good}
I guess this would be for_every_app.values.inject(true) {|good,x| good
= File.exists?(x) if good}
But I think the idea was clear.
On Aug 22, 2007, at 12:54 PM, Giles B. wrote:
So I’ve got this file-checking script:
def check
ok = true
for_every_app do |app,app_info|
ok = File.exists?(app_info[:root])
end
ok
end
this sends alarm bells ringing to me. i would expect, from that
small sample of code, that i could do
a_ok = apps.all?{|app| app.info.root.exist?}
which is to say apps is a method or collection, an app knows it’s
info, an info object knows it’s root, and that root is a Pathname
object so therefore has an exist method. which would obviate the
need for a method 
2cts.
a @ http://drawohara.com/
Alle mercoledì 22 agosto 2007, David A. Black ha scritto:
David
You’re right. Somehow, I thought that all? needed to iterate over all
the
values and any? didn’t. Of course, now I realized that, just as any?
will
stop at the first positive result, all? will stop at the first negative
result.
Stefano