Deleting a Hash from Array of Hashes in Ruby

Deleting a hash from array of hashes in Ruby

Use Array#delete_if:

arr = [{"k1"=>"v1", "k2"=>"75.1%"}, {"k1"=>"v2", "k2"=>"-NA-"}, {"k1"=>"v3", "k2"=>"5.1%"}]

arr.delete_if { |h| h["k1"] == "v3" }
#=> [{"k1"=>"v1", "k2"=>"75.1%"}, {"k1"=>"v2", "k2"=>"-NA-"}]

If there is no hash matching the condition, the array is left unchanged.

Remove Hash from array based on key in Ruby

Elements of the array are hashes, so you need to treat them as hashes:

@array.delete_if{|h| h[:total_duration] == 0}
# => [{:tid=>"m121459", :uid=>"S2G1", :total_duration=>713}]
@array
#=> [{:tid=>"m121459", :uid=>"S2G1", :total_duration=>713}] 

Remove key/value pair from array of hashes

Try the following code:

a = [
  {'id'=>'1','imageUrl'=>'abc','name'=>'x'},             
  {'id'=>'2','imageUrl'=>'efg','name'=>'y'},
  {'id'=>'3','imageUrl'=>'hij','name'=>'z'}
]

a.each { |h| h.delete("name") }

p a # => [{"id"=>"1", "imageUrl"=>"abc"}, {"id"=>"2", "imageUrl"=>"efg"}, {"id"=>"3", "imageUrl"=>"hij"}]

Delete item from Ruby array of hashes if item matches array of strings

It looks like your hash_list is missing some closing brackets. I've added them below. Try running this in irb:

playlist_track_names = ["I Might", "Me & You", "Day 1", "I Got You (feat. Nana Rogues)", "Feels So Good (feat. Anna of the North)", "306", "Location Unknown (feat. Georgia)", "Crying Over You (feat. BEKA)", "Shrink", "I Just Wanna Go Back", "Sometimes", "Forget Me Not"] 

hash_list = [
  {"id"=>"1426036284", "type"=>"songs", "attributes"=>{"name"=>"I Might", "albumName"=>"Love Me / Love Me Not" } },
  {"id"=>"1426036285", "type"=>"songs", "attributes"=>{"name"=>"Feels So Good (feat. Anna of the North)", "albumName"=>"Love Me / Love Me Not" } },
  {"id"=>"1426036286", "type"=>"songs", "attributes"=>{"name"=>"Forget Me Not", "albumName"=>"Love Me / Love Me Not" } },
  {"id"=>"1426036287", "type"=>"songs", "attributes"=>{"name"=>"Some Other Name", "albumName"=>"Love Me / Love Me Not" } }
]

hash_list.delete_if { |i| playlist_track_names.include? i["attributes"]["name"] }
puts hash_list

How to delete an array inside a hash

You can use transform_values and select the second element from the array in positions:

my_hash = {"positions"=>[[2, 3, 13, 56], [2, 3, 13]]}
wanted_hash = my_hash.transform_values { |value| value[1] }
# {"positions"=>[2, 3, 13]}

Notice it doesn't modify my_hash, it returns a new object.

Filter values from an array of hashes and delete them from the original array

Use partition to separate the input array into 2 arrays based on the filtering condition. You can modify the input array in place too, by using it on the left-hand side of the assignment:

my_array = [{ id: 1, val: 'foo' } , { id: 2, val: 'bar' } , { id: 3, val: 'baz' }]

# split input array into 2 new arrays, keep input array as is:
selected, other = my_array.partition { |hash| hash[:id] == 1 }

puts "#{selected}"   # [{:id=>1, :val=>"foo"}]
puts "#{other}"      # [{:id=>2, :val=>"bar"}, {:id=>3, :val=>"baz"}]

# remove from the input array selected elements into 1 new array,
# keep the rest in the input array (change the input array in-place):
selected, my_array = my_array.partition { |hash| hash[:id] == 1 }

puts "#{selected}"  # [{:id=>1, :val=>"foo"}]
puts "#{my_array}"  # [{:id=>2, :val=>"bar"}, {:id=>3, :val=>"baz"}]

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Note that partition can be thought of as both select and reject (or filter and reject) in a single operation. Here is a simple example to illustrate what partition does:

x, y = [3, 2, 1, 4].partition { |n| n < 3 }
puts "#{x}; #{y}"   # [2, 1]; [3, 4]

Remove an item from each hash in an Array of hashes

You can use map and delete

this will work the actual instances of the hashes, so the array will be modified.

array.each{ |hash| hash.delete('cat') }

you can do this to get a new array and keep the first one non touched.

new_array = array.map do |hash| 
   new_hash = hash.dup
   new_hash.delete('cat')
   new_hash
}

Deleting a specific hash inside an array of hashes using a variable

Try this:

arr.delete_if { |hash| id.include?(hash[:id]) }

Note (comparison to the #reject suggestion): #delete_if returns the unchanged array if there is nothing to delete. #reject returns nil. Also, #delete_if modifies the array in place, whereas #reject (without !) simply returns a changed version of the array but leaves the original unchanged.

edit
Note: the use of include? here assumes that there may be multiple integers that are being filtered out, i.e. if id (or ids) is actually an array. If you just need to filter one ID, you can use a straightforward comparison with hash[:id] == id inside the block. Thanks to smathy for pointing this out in the comments.

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