I have a nested array of hashes and am trying to get a copy so that i can delete from the copy without it affecting the original.
However this fails. This is what i am trying.
a = [[some_hash1, some_hash2],[some_hash_3]]
b == a.dup
b[0].delete_at(0)
After this code is executed, some_hash1 is gone from a
#dup produces a shallow copy of an object.
You could use marshalization:
a = [[{x: 2}, {y: 4}], [{z: 8}]]
b = Marshal.load(Marshal.dump(a))
b[0].delete_at(0)
puts a.to_s #=> [[{:x=>2}, {:y=>4}], [{:z=>8}]]
puts b.to_s #=> [[{:y=>4}], [{:z=>8}]]
If you are using Rails, you can use method deep_dup instead of Marshal.load,
$ a = [[{x: 2}, {y: 4}], [{z: 8}]]
$ # => [[{:x=>2}, {:y=>4}], [{:z=>8}]]
$ b = a.deep_dup
$ # => [[{:x=>2}, {:y=>4}], [{:z=>8}]]
$ b[0].delete_at(0)
$ #=> {:x=>2}
$ b
$ # => [[{:y=>4}], [{:z=>8}]]
$ a
$ # => [[{:x=>2}, {:y=>4}], [{:z=>8}]]
Of course, you have to use solution provided by @Danil if you are using only Ruby without Rails
