select!

[Roger Pack]

Is there any reason there's no select!
(and I am familiar with compact! but still...)

C:\>ruby -e 'puts [].methods.grep /reject/'
reject
reject!

C:\>ruby -e 'puts [].methods.grep /select/'
select

 

[Ryan Davis]

Is there any reason there's no select!

Perhaps because `select! x` is as simple as `reject! not x`?

 

[David Masover]

Perhaps because `select! x` is as simple as `reject! not x`?

For consistency's sake, I'd still suggest the standard library should provide
something like:

module Enumerable
def select!
reject! {|*args| ! yield(*args) }
end
def reject!
select! {|*args| ! yield(*args) }
end
end

Not exactly that, though -- the obvious problem is that if neither select! no
reject! is overridden, you'd want a NoMethodError instead of a stack overflow.

 

[Roger Pack]

For consistency's sake, I'd still suggest the standard library should
provide
something like:

module Enumerable
def select!
reject! {|*args| ! yield(*args) }
end
def reject!
select! {|*args| ! yield(*args) }
end
end

Anybody in favor of select!
Could comment on
http://redmine.ruby-lang.org/issues/show/2515

-r

 

[Rick DeNatale]

-1

Enumerable does not have a reject! since not all Enumerables are
mutable either in general or during enumeration.

Also the given suggestion would lead to infinite loops, unless reject!
or select! was overridden in the including class.



--=20
Rick DeNatale

Blog: http://talklikeaduck.denhaven2.com/
Twitter: http://twitter.com/RickDeNatale
WWR: http://www.workingwithrails.com/person/9021-rick-denatale
LinkedIn: http://www.linkedin.com/in/rickdenatale

 

[Robert Klemme]

Is there any reason there's no select!
(and I am familiar with compact! but still...)

C:\>ruby -e 'puts [].methods.grep /reject/'
reject
reject!

C:\>ruby -e 'puts [].methods.grep /select/'
select

Maybe Matz felt that using "select" to actually _delete_ from an Array
would be considered weird. And indeed, we have #delete, #delete_at
and #delete_if:

irb(main):001:0> Array.instance_methods.grep /delete/
=> [:delete, :delete_at, :delete_if]
irb(main):002:0>



Kind regards

robert

 

[Roger Pack]

Enumerable does not have a reject! since not all Enumerables are
mutable either in general or during enumeration

Yeah this is a feature request only for Array#select!

[Enumerable doesn't have a reject! nor should it have a select!]

Maybe Matz felt that using "select" to actually _delete_ from an Array
would be considered weird. And indeed, we have #delete, #delete_at
and #delete_if:

His words:

Enumerables cannot have bang method, since they are not always
mutable. The reason we don't have Array#select! is that I feel the
word select means picking up elements, not removing non-selecting
elements. But I once felt same way to map! and (English speaking)
people persuaded me, so same thing could happen on select! as well.

So yes but hopefully I can change his mind

-r

 

[Phillip Gawlowski]

His words:


So yes but hopefully I can change his mind

The second "SELECT * FROM TABLE" deletes the records I want to retrieve
from a DBMS, I agree with you.