Ruby equivalent to Python chain()

Question

What is the Ruby equivalent of the chain iterator in python?

data_chained = []
data2 = {}     
data_chained = chain(data_chained, data2)

How can this be done in Ruby?

Possible duplicate of [What's the Ruby equivalent of Python \`itertools.chain\`?](https://stackoverflow.com/questions/27919677/whats-the-ruby-equivalent-of-python-itertools-chain) — zvone, Mar 24 '19 at 20:16
Are you referring to `itertools.chain`? That operates on iterables; using it on dictionaries is kind of... weird. — Aran-Fey, Mar 24 '19 at 20:17

score 3 · Accepted Answer · answered Mar 24 '19 at 23:39

3

Since Ruby 2.6: if it is Enumerable, you can chain it: (example from the docs, chaining a Range to an Array)

e = Enumerator::Chain.new(1..3, [4, 5]) 
e.to_a #=> [1, 2, 3, 4, 5]
e.size #=> 5

answered Mar 24 '19 at 23:39

steenslag

79,051
16
138
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score 0 · Answer 2 · answered Mar 24 '19 at 21:05

Is this what you are looking for?

Hash#merge

You use it like below:

h1 = { "a" => 100, "b" => 200 }
h2 = { "b" => 254, "c" => 300 }
h1.merge(h2)   #=> {"a"=>100, "b"=>254, "c"=>300}
h1.merge(h2){|key, oldval, newval| newval - oldval}
       #=> {"a"=>100, "b"=>54,  "c"=>300}
h1             #=> {"a"=>100, "b"=>200}

score 0 · Answer 3 · answered Mar 25 '19 at 18:22

0

I misunderstood the issue, it may be the same as itertools.chain in python. This worked for me ->

Enumerator::Chain.new(data_chained, data2)

answered Mar 25 '19 at 18:22

Ashima Sood

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Ruby equivalent to Python chain()

3 Answers3