I'd like to delete an item in my loop i have a array of instance of my class, and i need sometimes to delete this items from my array
class Test
attr_reader :to_del
def initialize(str)
@to_del = str
end
end
tab = Array.new
a = Test.new(false)
b = Test.new(true)
c = Test.new(false)
tab.push(a)
tab.push(b)
tab.push(c)
for l in tab
if l.to_del == true
l = nil
end
end
p tab
any idea ?
For inplace deletion:
tab.reject! { |l| l.to_del }
to return just a cleared array:
tab.reject &:to_del
The whole code is php-smelled. I would go with:
tab = (1..3).map { [true,false].sample }.map { |e| Test.new e }
tab.reject &:to_del
tab.reject!(&:to_del) shortcut.
Symbol#to_proc is actually faster than using an explicit block.Benchmark.bm { |x| x.report { n.times { [1,2,3].map { |i| i.to_s } } } ; x.report { n.times { [1,2,3].map &:to_s } } } ⇒ [2.39, 2.71]. Please don’t make unfounded declarations.Array.new(3) { ... } or 3.times.map { ... } to (1..3).map { ... } since the indices aren't important.3.times and Array.new(3) are more semantic.You can use Array#delete_if.
Check this out:
tab
#=> [#<Test:0x00000007548768 @to_del=false>, #<Test:0x000000074ea348 @to_del=true>, #<Test:0x000000074b21a0 @to_del=false>]
tab.delete_if {|x| x.to_del}
#=> [#<Test:0x00000007548768 @to_del=false>, #<Test:0x000000074b21a0 @to_del=false>]
tab = [Test.new(false), Test.new(true), Test.new(false)]. As you gain experience with Ruby you'll find thatforis very rarely used. (I've never used it.) That's because it's almost always better to employ a method that enumerates the elements of the receiver (here an array), as has been done by in both answers so far.