array sort_by with nil elements

[Josselin]

I am using the sort_by command

@buddies = @user.buddies.compact.sort_by {|item| item.send @criteria}


problem arise when one criteria like the user.name is nil the sort
crash.... anyway to avoid it

thanks a lot for your lights

joss

 

[Robert Klemme]

I am using the sort_by command

@buddies = @user.buddies.compact.sort_by {|item| item.send @criteria}


problem arise when one criteria like the user.name is nil the sort
crash.... anyway to avoid it

Add a rescue modifier.

@buddies = @user.buddies.compact.sort_by {|item| item.send @criteria rescue nil}

Kind regards

robert

 

[Stefan Rusterholz]

I am using the sort_by command

@buddies = @user.buddies.compact.sort_by {|item| item.send @criteria}


problem arise when one criteria like the user.name is nil the sort
crash.... anyway to avoid it

thanks a lot for your lights

joss

Simply add a default value (best one that gets sorted in the beginning
or the end)
@buddies = @user.buddies.compact.sort_by {|item| item.send(@criteria) ||
default }


Regards
Stefan

 

[Robert Klemme]

Simply add a default value (best one that gets sorted in the beginning
or the end)
@buddies = @user.buddies.compact.sort_by {|item| item.send(@criteria) ||
default }

This does not work.

irb(main):003:0> [nil].sort_by {|it| it.sendlength) || 0}
NoMethodError: undefined method `length' for nil:NilClass
from (irb):3:in `send'
from (irb):3
from (irb):3:in `sort_by'
from (irb):3:in `each'
from (irb):3:in `sort_by'
from (irb):3
from :0

You actually need to deal with the exception or test beforehand that
the item responds to the method.

Kind regards

robert

 

[F. Senault]

Le 19 juillet à 14:32, Robert Klemme a écrit :

This does not work.

irb(main):003:0> [nil].sort_by {|it| it.sendlength) || 0}

[nil, "aaaaaaa", "aaa", "a" ].sort_by {|it| (it && it.sendlength)) || 0}

=> [nil, "a", "aaa", "aaaaaaa"]

(Or even without the parenthesis.)

Fred

 

[Stefan Rusterholz]

This does not work.

irb(main):003:0> [nil].sort_by {|it| it.sendlength) || 0}

Kind regards

robert

According to him, his problem is not the *element* being nil, but the
*method called upon* returning nil. So yes, this does work for the
problem he describes.
Regards
Stefan

 

[Robert Klemme]

This does not work.

irb(main):003:0> [nil].sort_by {|it| it.sendlength) || 0}

According to him, his problem is not the *element* being nil, but the
*method called upon* returning nil. So yes, this does work for the
problem he describes.

I stand corrected. Sorry for the noise.

Kind regards

robert

 

[Josselin]

This does not work.

irb(main):003:0> [nil].sort_by {|it| it.sendlength) || 0}

Kind regards

robert

According to him, his problem is not the *element* being nil, but the
*method called upon* returning nil. So yes, this does work for the
problem he describes.
Regards
Stefan

yes you're right , I did not mention it (even thought...) the element
'user' always exist... but user can have nil display_name....

thanks to all , I keep that in my book !