Array#delete_if: can I get the deleted elements

[Raphael Bauduin]

Hi,

applying the example found in "ri Array#delete_if":

irb(main):020:0> a = [ "a", "b", "c" ]
=> ["a", "b", "c"]
irb(main):021:0> a.delete_if {|x| x >= "b" }
=> ["a"]
irb(main):022:0> a
=> ["a"]

How do I get the elements that where rejected? (Btw, shouldn't this
method end in a "!" ?)

As illustration, I'm looking for a way similar to the pure fictional
method below:
a = [ "a", "b", "c" ]
a.keep_if {|x| x >= "b" }
=> [ "b", "c" ]

Thanks

Raph

 

[Jason Williams]

Hi,

applying the example found in "ri Array#delete_if":

irb(main):020:0> a = [ "a", "b", "c" ]
=> ["a", "b", "c"]
irb(main):021:0> a.delete_if {|x| x >= "b" }
=> ["a"]
irb(main):022:0> a
=> ["a"]

How do I get the elements that where rejected? (Btw, shouldn't this
method end in a "!" ?)

How about instead;

x,y = a.partition { |x| x >= "b" }

The "!" isn't necessary IMO because "delete" already implies the
destructive in-place effect. The not-in-place version is reject_if.

As illustration, I'm looking for a way similar to the pure fictional
method below:
a = [ "a", "b", "c" ]
a.keep_if {|x| x >= "b" }
=> [ "b", "c" ]

a.select { |x| x >= "b" }

 

[Andrew Walrond]

As illustration, I'm looking for a way similar to the pure fictional
method below:
a = [ "a", "b", "c" ]
a.keep_if {|x| x >= "b" }
=> [ "b", "c" ]

a = [ "a", "b", "c" ]
b = Array.new
a.each { |x| b.push(x) if x >="b" }

 

[Raphael Bauduin]

Hi,

applying the example found in "ri Array#delete_if":

irb(main):020:0> a = [ "a", "b", "c" ]
=> ["a", "b", "c"]
irb(main):021:0> a.delete_if {|x| x >= "b" }
=> ["a"]
irb(main):022:0> a
=> ["a"]

How do I get the elements that where rejected? (Btw, shouldn't this
method end in a "!" ?)

How about instead;

x,y = a.partition { |x| x >= "b" }

The "!" isn't necessary IMO because "delete" already implies the
destructive in-place effect. The not-in-place version is reject_if.

As illustration, I'm looking for a way similar to the pure fictional
method below:
a = [ "a", "b", "c" ]
a.keep_if {|x| x >= "b" }
=> [ "b", "c" ]

a.select { |x| x >= "b" }

Great!

thanks.

Raph

 

[Andrew Walrond]

x,y = a.partition { |x| x >= "b" }

You learn something every day Time to reread the pickaxe to relearn stuff
I obviously missed the first time

 

[Simon Strandgaard]

You learn something every day Time to reread the pickaxe to relearn stuff
I obviously missed the first time

Array#partition is unfortunatly not documented in pickaxe...

Take a look at 'array.c' in rubys source and you will find many other
not-yet-documented methods.

 

[Robert Klemme]

Array#partition is unfortunatly not documented in pickaxe...

Take a look at 'array.c' in rubys source and you will find many other
not-yet-documented methods.

With a little bit of guessing this irb can help with this, too:

Array.new.public_methods - Array.superclass.public_methods

robert

 

[Jason Williams]

With a little bit of guessing this irb can help with this, too:

Array.new.public_methods - Array.superclass.public_methods

Also, whytheluckystiff's "What's Shiny and New in Ruby 1.8.0" -

http://whytheluckystiff.net/articles/2003/08/04/rubyOneEightOh

 

[gabriele renzi]

il Mon, 27 Oct 2003 15:11:25 +0000, Andrew Walrond

You learn something every day Time to reread the pickaxe to relearn stuff
I obviously missed the first time

try the latest ri or rj (on rubyforge), this is now my pirmary source
of information.. (waiting for pickaxe2)

 

[Andrew Walrond]

try the latest ri or rj (on rubyforge), this is now my pirmary source
of information.. (waiting for pickaxe2)

I've got ri; what's rj ??

 

[gabriele renzi]

il Mon, 27 Oct 2003 21:02:24 +0000, Andrew Walrond

I've got ri; what's rj ??

http://rubyforge.org/projects/rjay/
ypou have to get the cvs yourself..