Conditional block operations

ruby-talk
1

Hi,

From: “Roman Rytov” rrytov@entopia.com
Reply-To: ruby-talk@ruby-lang.org
To: ruby-talk@ruby-lang.org (ruby-talk ML)
Subject: Conditional block operations
Date: Tue, 3 Dec 2002 22:58:15 +0900

Is there a way to filter results of EACH or COLLECT functions? Let’s say
in

file.each do |line|
a, b = line.split(pattern)
End

I think for this case, the easist way might be

file.each do |line|
a, b = line.split(pattern) if line !~ /^\s*$/
end

But for the next one, I have no idea. I think it has something related to
array.each and array.each_index, because in collect, the |x| seems is the
element itself, not the index. For example.

myarray.collect {|x| x + ", "}

myarray.each_index do |i|
myarray[i]+=", " if i%2
end

Shannon

···

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2

Shannon Fang wrote:

Hi,

From: “Roman Rytov” rrytov@entopia.com
Reply-To: ruby-talk@ruby-lang.org
To: ruby-talk@ruby-lang.org (ruby-talk ML)
Subject: Conditional block operations
Date: Tue, 3 Dec 2002 22:58:15 +0900

Is there a way to filter results of EACH or COLLECT functions? Let’s say
in

file.each do |line|
a, b = line.split(pattern)
End

I think for this case, the easist way might be

file.each do |line|
a, b = line.split(pattern) if line !~ /^\s*$/
end

grep could help, unfortunately I don’t know if it can be negated (eg
“all but the matches”).

emmanuel

···

–
“If someone breaks into my house and steals my CDs,
who calls the cops, me or the music industry?
If it’s me, then that’s my property.”
–Ruben Safir

3

Emmanuel Touzery wrote:

Shannon Fang wrote:

I think for this case, the easist way might be

file.each do |line|
a, b = line.split(pattern) if line !~ /^\s*$/
end

grep could help, unfortunately I don’t know if it can be negated (eg
“all but the matches”).

emmanuel

actually \S is “non whitespace character”, so this is ok:

file.grep /^\S+$/ do |line|
a, b = line.split pattern
end

emmanuel

···

–

“If someone breaks into my house and steals my CDs,
who calls the cops, me or the music industry?
If it’s me, then that’s my property.”
–Ruben Safir