Rails - do a logic operation on each row of an activerecord result

Question

I have a model that has a column of type Boolean.

It's possible to retrieve "on the fly" (without iterating all the result) the result of a logic calculus?

For example:

data = Model.limit(10)
# I would like to know if each data.column is true
# the result is something to this logic: data[0].column && data[1].column && ...
# ..but there is one manner to do this without iterating?

Using the main conditions: AND, OR, XOR (the conditions are all the same - all AND or all OR ,...).

Maybe you can treat true as 1 and false as 0. You can easily fetch SUM(column). If SUM(column) == Model.count, it means that all records have column = true. If SUM(column) == 0, it means that all are false. You can easily extend solution to return two additional fields, like number_of_trues [ 1 if true, 0 if false ] and number_of_falses [ 0 if true, 1 if false ]. If you want to know, if all are true, just check if number_of_falses is 0 etc — mkk, Aug 05 '13 at 11:03
@mkk this is a good solution if you must build from scratch the model too. If the model already exists I think that is better the solution suggested by Ryan Bigg — damoiser, Aug 05 '13 at 12:40

score 1 · Accepted Answer · answered Aug 05 '13 at 11:47

1

records = Model.limit(10).all
records.all? { |r| r.column? }

I think all? is what you're looking for.

answered Aug 05 '13 at 11:47

Ryan Bigg

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Thanks Ryan, it is was I looking for. I'dont known the method "all?" – damoiser Aug 05 '13 at 12:37

Rails - do a logic operation on each row of an activerecord result

1 Answers1