CODEWITHSUNDEEP
ruby
Mark Locklear
Mark Locklear

Reputation: 5325

Ruby from two dimension to one dimension array

I have the following array:

arr = [
 "Assignment:Chapter 1 Code Exercises (Real)",
 [100, 100, 100, 100, 100, 100, 100, 100],
 "Assignment:Chapter 2 Code Exercises (Real)", 
 [93, 75, 100, 100, 100, 55, 75, 100],
 "Assignment:Chapter 3 Code Exercises (Real)",
 [100, 80, 100, 100, 90, 85, 65, 100],
 "Assignment:Chapter 4 Code Exercises (Real)",
 [100, 90, 100, 100, 95, 100, 75, 70],
 "Assignment:Chapter 5 Code Exercises (Real)",
 [50, 100, 100, 100, 60, 70, 90, 100],
 "Assignment:Chapter 6 Code Exercises (Real)",
 [0, 85, 100, 100, 60, 85, 70, 85, 100],
 "Assignment:Chapter 14 Code Exercises (Real)",
 [75, 90, 100, 100, 0, 100, 0, 100],
 "Assignment:Chapter 15 Code Exercises (Real)",
 [97, 100, 100, 100, 0, 100, 0, 100]
]

I would like to convert this to:

[
 ["Assignment:Chapter 1 Code Exercises (Real)", 100, 100, 100, 100, 100, 100, 100, 100], 
 ["Assignment:Chapter 2 Code Exercises (Real)", 93, 75, 100, 100, 100, 55, 75, 100],
 ["Assignment:Chapter 3 Code Exercises (Real)", 100, 80, 100, 100, 90, 85, 65, 100],
 ["Assignment:Chapter 4 Code Exercises (Real)", 100, 90, 100, 100, 95, 100, 75, 70],
 ["Assignment:Chapter 5 Code Exercises (Real)", 50, 100, 100, 100, 60, 70, 90, 100],
 ["Assignment:Chapter 6 Code Exercises (Real)", 0, 85, 100, 100, 60, 85, 70, 85], 100],
 ["Assignment:Chapter 14 Code Exercises (Real)", 75, 90, 100, 100, 0, 100, 0, 100],
 ["Assignment:Chapter 15 Code Exercises (Real)", 97, 100, 100, 100, 0, 100, 0, 100]
]

flatten so too "flat". I also tried flatten(1).

Upvotes: 1

Views: 77

Answers (2)

Matt
Matt

Reputation: 20776

> Hash[*a].map(&:flatten)
=> 
[["Assignment:Chapter 1 Code Exercises (Real)", 100, 100, 100, 100, 100, 100, 100, 100],
 ["Assignment:Chapter 2 Code Exercises (Real)", 93, 75, 100, 100, 100, 55, 75, 100],
 ["Assignment:Chapter 3 Code Exercises (Real)", 100, 80, 100, 100, 90, 85, 65, 100],
 ["Assignment:Chapter 4 Code Exercises (Real)", 100, 90, 100, 100, 95, 100, 75, 70],
 ["Assignment:Chapter 5 Code Exercises (Real)", 50, 100, 100, 100, 60, 70, 90, 100],
 ["Assignment:Chapter 6 Code Exercises (Real)", 0, 85, 100, 100, 60, 85, 70, 85, 100],
 ["Assignment:Chapter 14 Code Exercises (Real)", 75, 90, 100, 100, 0, 100, 0, 100],
 ["Assignment:Chapter 15 Code Exercises (Real)", 97, 100, 100, 100, 0, 100, 0, 100]]

where a is the first array above.

Alternatively, taking @CarySwoveland's recommendation:

a.each_slice(2).map(&:flatten)

is more efficient w/ both time and memory, and doesn't require the strings to be unique.

Upvotes: 2

spickermann
spickermann

Reputation: 106792

array.each_slice(2).map { |(x,y)| [x] + y }
#=> [["Assignment:Chapter 1 Code Exercises (Real)", 100, 100, 100, 100, 100, 100, 100, 100],               
#    ["Assignment:Chapter 2 Code Exercises (Real)", 93, 75, 100, 100, 100, 55, 75, 100],                   
#    ["Assignment:Chapter 3 Code Exercises (Real)", 100, 80, 100, 100, 90, 85, 65, 100],                   
#    ["Assignment:Chapter 4 Code Exercises (Real)", 100, 90, 100, 100, 95, 100, 75, 70],                   
#    ["Assignment:Chapter 5 Code Exercises (Real)", 50, 100, 100, 100, 60, 70, 90, 100],            
#    ["Assignment:Chapter 6 Code Exercises (Real)", 0, 85, 100, 100, 60, 85, 70, 85, 100],          
#    ["Assignment:Chapter 14 Code Exercises (Real)", 75, 90, 100, 100, 0, 100, 0, 100],             
#    ["Assignment:Chapter 15 Code Exercises (Real)", 97, 100, 100, 100, 0, 100, 0, 100]]

Upvotes: 4

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