How to (better) check for element existence within multidimensional array?

Question

How do I avoid doing this?

if boolean_array[day] && boolean_array[day][slot] && boolean_array[day][slot].zero?
  # boolean_array[day][slot] element exists
end

Chuck · Accepted Answer · 2009-11-04 23:04:08Z

7

Basically, you want an andand method. You can then do if boolean_array[day].andand[slot].andand.zero?.

Raganwald has one popular implementation.

answered Nov 4, 2009 at 23:04

Chuck

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1 Comment

Alexandre Over a year ago

Looks like the answer. Mind waiting to see if anybody else has some other suggestion?

Community · Accepted Answer · 2017-05-23 10:34:18Z

2

I like Chuck's andand. I suppose you could also use the low-priority and to do it in plain Ruby, at least there would be no parens:

>> day = slot = 1; boolean_array = [[], [1,2]]

>> if t = boolean_array[day] and t = t[slot] and t = t.class
>>   puts t
>> end
Fixnum

edited May 23, 2017 at 10:34

CommunityBot

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answered Nov 5, 2009 at 1:07

DigitalRoss

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Comments

JRL · Accepted Answer · 2009-11-05 01:15:09Z

1

One alternative is to use an inline rescue:

boolean_array[day][slot].zero? rescue nil

answered Nov 5, 2009 at 1:15

JRL

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cgr · Accepted Answer · 2009-11-05 04:24:00Z

0

if possible, initialize the days and that way you can do the check for boolean_array[day][slot].nil?

answered Nov 5, 2009 at 4:24

cgr

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sawa · Accepted Answer · 2011-04-01 13:27:50Z

0

You can do it without additional gems. Depending on what you have as the value, change to_i to to_f, etc.

if boolean_array[day].to_a[slot].to_i.zero?
  # boolean_array[day][slot] element exists
end

answered Apr 1, 2011 at 13:27

sawa

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