Array Growth

There are a variety of ways to add items to an array.

In the beginning…

There was #unshift. If you want to add something in the beginning, use it.

how_much = ["many", "slams", "in", "an", "old", "screen", "door"]

how_much.unshift("how")
=> ["how", "many", "slams", "in", "an", "old", "screen", "door"]

In the end…

You can always use #push, which could handle just one or multiple arguments. There’s also fun to be had in chaining it.

how_much =["how", "many", "slams", "in", "an", "old", "screen", "door"]

how_much.push("depends")
=> ["how", "many", "slams", "in", "an", "old", "screen", "door", "depends"]

how_much.push("how", "loud")
=> ["how", "many", "slams", "in", "an", "old", "screen", "door", "depends", "how", "loud"]

how_much.push("you").push("shut").push("it")
=> ["how", "many", "slams", "in", "an", "old", "screen", "door", "depends", "how", "loud", "you", "shut", "it"]

The same fun can be had with #<<

how_much = ["how", "many", "slices", "in", "a", "bread"]

how_much << "depends"
=> ["how", "many", "slices", "in", "a", "bread", "depends"]

how_much << ["how", "thin"]
=> ["how", "many", "slices", "in", "a", "bread", "depends", ["how", "thin"]]

how_much << "you" << "cut" << "it"
=> ["how", "many", "slices", "in", "a", "bread", "depends", ["how", "loud"], "you", "cut", "it"]

Everywhere else

With #insert, we can give an index to indicate where we’d like things to go before giving the object(s) that will be going there. Notice that it pushes things around to accommodate our request that this new object goes where we want and everything else needs to fall in line.

how_many = ["how", "much", "inside", "a", "day"]

how_many.insert(2, "good")
=> ["how", "much", "good", "inside", "a", "day"]

how_many.insert(-1, "depends", "how", "good", "you", "live")
=> ["how", "much", "good", "inside", "a", "day", "depends", "how", "good", "you", "live"]

 

“How Many, “How Much” -Shel Silverstein

How many slams in an old screen door?
Depends how loud you shut it.
How many slices in a bread?
Depends how thin you cut it.
How much good inside a day?
Depends how good you live ’em.
How much love inside a friend?
Depends how much you give ’em.

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