ruby remove item from array based on another array

Question

i have two data,

{:date=>"2015-09-23", :time=>["13:30"]}
{:date=>"2015-09-23", :time=>["12:00"]}
...more

and i try to remove this from

{:date=>"2015-09-21", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}
{:date=>"2015-09-22", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}
{:date=>"2015-09-23", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}
{:date=>"2015-09-24", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}

and the output i hope can get

{:date=>"2015-09-21", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}
{:date=>"2015-09-22", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}
{:date=>"2015-09-23", :time=>["12:30", "13:00", "14:00", "14:30"]}
{:date=>"2015-09-24", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}

i was try

removeAry.each do |b|
  if b[:date] == "2015-09-23"
    puts b[:time].to_s.delete("13:30")
  end
end

do have any better idea ?

I think you can always make life much easier if you always consider how to store your data according to you application needs. For example, if you have a an array of hashes as such: [{:"2015-09-21" => ["12:00", "12:30", "13:00", "13:30"]}. In this case you can traverse through you structure using array index and then grap your hash using key,value pairs. Key being the day, and value would be an array of time stamps. — moeabdol
– moeabdol, Commented Sep 21, 2015 at 11:27

moeabdol · Accepted Answer · 2015-09-21 12:47:52Z

1

If you have control over how your data is represented then you might consider simplifying your data as such:

The data you want removed

{:"2015-09-23" => ["12:00", "13:30"]}

Data to be removed from

[{:"2015-09-21" => ["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]},
 {:"2015-09-22" => ["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]},
 {:"2015-09-23" => ["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]},
 {:"2015-09-24" => ["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}]

The output you want achieved

[{:"2015-09-21" => ["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]},
 {:"2015-09-22" => ["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]},
 {:"2015-09-23" => ["12:30", "13:00", "14:00", "14:30"]},
 {:"2015-09-24" => ["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}]

By doing this you can now:

target = {:"2015-09-23" => ["12:00", "13:30"]}
input = [{:"2015-09-21" => ["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]},
     {:"2015-09-22" => ["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]},
     {:"2015-09-23" => ["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]},
     {:"2015-09-24" => ["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}]

input.each do |hash|
  hash.each do |key, value|
    if key == target.keys[0]
      target.values.each do |t_value|
        hash[key].delete(t_value)
      end
    end
  end
end

Hope this helps.

edited Sep 21, 2015 at 12:47

answered Sep 21, 2015 at 12:20

moeabdol

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2 Comments

moeabdol Over a year ago

Please let me know if this doesn't fit your solution so I can enhance the answer. Thanks.

user7331 Over a year ago

thanks, but i can't change the data format. and i try too many time, each time they delete all date time, for example, if i need delete "2015-09-23" "13:00", return will delete all date "13:00"

Aleksey Shein · Accepted Answer · 2015-09-21 12:56:04Z

0

Ok, here's what I would do:

require 'set'

to_delete = [
  {:date=>"2015-09-23", :time=>["13:30"]},
  {:date=>"2015-09-23", :time=>["12:00"]}
]

data = [
  {:date=>"2015-09-21", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]},
  {:date=>"2015-09-22", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]},
  {:date=>"2015-09-23", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]},
  {:date=>"2015-09-24", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}
]

# convert to_delete array to a hash { "2015-09-23" => #<Set: {"13:30", "12:00"}> }
# we use Set here to store only unique time values
to_delete_as_hash = to_delete.reduce({}) do |acc, item|
  acc[item[:date]] ||= Set.new
  acc[item[:date]] += item[:time]
  acc
end

filtered = data.map do |item|
  # skip this item if there's no need to process this date
  next item unless to_delete_as_hash[item[:date]]
  # subtract to_delete values from current item[:time] values
  item[:time] -= to_delete_as_hash[item[:date]].to_a
  item
end

p filtered

Output:

[
    {:date => "2015-09-21", :time => ["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]},
    {:date => "2015-09-22", :time => ["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]},
    {:date => "2015-09-23", :time => ["12:30", "13:00", "14:00", "14:30"]},
    {:date => "2015-09-24", :time => ["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}
]

answered Sep 21, 2015 at 12:56

Aleksey Shein

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2 Comments

user7331 Over a year ago

one more tricky question. how add condition, if [to_delete] data, no time, just date, need delete that date from data. i'm try modify code now, if you have any advance how to make it, please kind let me know. thanks you so much for your help.

Aleksey Shein Over a year ago

It is not clear from your comment what input and output you want to achieve. Could you update your question with examples, just as you did the first time? Thank you.

Community · Accepted Answer · 2020-06-20 09:12:55Z

0

First define your test data

data = [{:date=>"2015-09-21", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}, {:date=>"2015-09-22", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}, {:date=>"2015-09-23", :time=>["12:30", "13:00", "14:00", "14:30"]}, {:date=>"2015-09-24", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}]

to_delete = {:date=>"2015-09-23", :time=>["13:30"]}

Main code

data.select{|x| x if x[:date] == to_delete[:date]}.each{|x| x.delete(to_delete[:time])}

You can also store to_delete in array and iterate over it.

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Sep 21, 2015 at 11:17

Adrián Fernández

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2 Comments

Borsunho Over a year ago

Why not data.select{|x| x[:date] == to_delete[:date]}? Select only cares if return value of a block is truthy, or am I wrong?

user7331 Over a year ago

data.select{|x| x if x[:date] == to_delete[:date]}.each{|x| x.delete(to_delete[:time])} this not work, but data.select{|x| x if x[:date] == to_delete[0][:date]}.each{|x| x.delete(to_delete[0][:time])} why ?

Rokibul Hasan · Accepted Answer · 2015-09-21 12:01:24Z

0

I have rewrite your code as following

data = [{:date=>"2015-09-21", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}, 
        {:date=>"2015-09-22", :time=>["12:00", "12:30", 13:00", "13:30", "14:00", "14:30"]},
        {:date=>"2015-09-23", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]},
        {:date=>"2015-09-24", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}]

And Function to manipulate hash

def output_hash(data, p_date="2015-09-23", p_time="13:30")
    output = data.collect do |key, value|
      if key[:date] == p_date
         key[:time].delete!(p_time) if key[:time].include?(p_time) 
         time =  key[:time]
         key.delete(:time)
         key.merge!(:time => time)
       else 
         key
       end
    end
    return output
end

will generate following output

 [{:date=>"2015-09-21", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}, 
  {:date=>"2015-09-22", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]},
  {:date=>"2015-09-23", :time=>["12:00", "12:30", "13:00", "14:00", "14:30"]},
  {:date=>"2015-09-24", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}]

edited Sep 21, 2015 at 12:01

answered Sep 21, 2015 at 11:53

Rokibul Hasan

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2 Comments

user7331 Over a year ago

how it work if have another date and another time ? like : {:date=>"2015-09-24", :time=>["14:30"]}

Rokibul Hasan Over a year ago

very simple you have to pass two params p_date and p_time, then use that into the function with rap a method name. See the edited answer rape with a method.

pangpang · Accepted Answer · 2015-09-21 12:05:42Z

0

have a try:

removeAry.map { |h| h[:date] == "2015-09-23" ? (h[:time].delete("13:30");h) : h }

or:

def removeAry.function(date, time)
  self.map { |h| h[:date] == date ? (h[:time].delete(time);h) : h }
end

removeAry.function("2015-09-23", "13:30")

edited Sep 21, 2015 at 12:05

answered Sep 21, 2015 at 11:44

pangpang

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2 Comments

user7331 Over a year ago

if have data with different date, like: {:date=>"2015-09-26", :time=>["12:00"]} this not work...

pangpang Over a year ago

@user7331you can define a method, date and time as arguments.

Shiva · Accepted Answer · 2015-09-21 13:13:40Z

hash = [
    {:date => "2015-09-21", :time => ["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]},
    {:date => "2015-09-22", :time => ["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]},
    {:date => "2015-09-23", :time => ["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]},
    {:date => "2015-09-24", :time => ["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}
]

comparables = [
    {:date => "2015-09-23", :time => ["13:30"]},
    {:date => "2015-09-23", :time => ["12:00"]}
]

hash.each do |new_hash|
  comparables.each do |comparable|
    if new_hash[:date] == comparable[:date]
      new_hash[:time] = new_hash[:time] - comparable[:time]
    end
  end
end

puts hash

Output

user@ubuntu:~$ ruby test.rb 
{:date=>"2015-09-21", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}
{:date=>"2015-09-22", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}
{:date=>"2015-09-23", :time=>["12:30", "13:00", "14:00", "14:30"]}
{:date=>"2015-09-24", :time=>["12:00", "12:30", "13:00", "13:30", "14:00", "14:30"]}

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