[RAILS] [Ruby] I want to make an array from a character string with the split method. And vice versa.

What kind of writing will give the expected value when the pattern is to arrange the character strings and make the array into a character string?

So, let's organize it with some bad patterns!

Make a string an array

We will use the split method.

** split English translation: split ** In other words, it is a method that divides a cohesive object (character string, etc.) into elements. (Arrangement) The argument is * an image that specifies the boundary of the part to be cut *

I tried to arrange from various cohesive patterns. The array you want to have is [" foo "," bar "," baz "].

Now, which writing style is right for you?

#Arrangement#Return value
"foo bar baz".split           ["foo", "bar", "baz"]  # ○
"foo bar baz".split('')	      ["f", "o", "o", " ", "b", "a", "r", " ", "b", "a", "z"]
"foo bar baz".split(',')      ["foo bar baz"]

"foobarbaz".split             ["foobarbaz"]
"foobarbaz".split('')         ["f", "o", "o", "b", "a", "r", "b", "a", "z"]
"foobarbaz".split(',')        ["foobarbaz"]
"fooxbarxbaz".split('x')      ["foo", "bar", "baz"]  # ○

"foo, bar, baz".split         ["foo,", "bar,", "baz"]
"foo, bar, baz".split('')     ["f", "o", "o", ",", " ", "b", "a", "r", ",", " ", "b", "a", "z"]
"foo, bar, baz".split(',')    ["foo", " bar", " baz"]

"foo,bar,baz".split           ["foo,bar,baz"]
"foo,bar,baz".split('')       ["f", "o", "o", ",", "b", "a", "r", ",", "b", "a", "z"]
"foo,bar,baz".split(',')      ["foo", "bar", "baz"]  # ○

%w[foo bar baz]               ["foo", "bar", "baz"]  # ○

From this, there are * 4 ways * of how to write the expected array.

I want to change from an array to a character string

We will use the join method. It will be an image of inserting the value to be inserted between * elements in the argument *.

#Stringification#Return value
["foo", "bar", "baz"].join        "foobarbaz"
["foo", "bar", "baz"].join('')    "foobarbaz"
["foo", "bar", "baz"].join(',')	  "foo, bar, baz"

Extra range array

#Arrange the range#Return value
(0..9).to_a                 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
('a'..'z').to_a             ["a",..,"z"]
(1..5).map{ |i| i**2 )      [0, 1, 4, 9, 16, 25, 36, 49, 64, 81]

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