Question

I have a 2d array of the following form:

[  [(,  (,  (,  (,  (,],
   [1.0,1.0,1.0,1.0,1.0,], 
   [+,  +,  +,  +,  +,],
   [2.0,2.0,2.0,2.0,2.0,],
   [),  ),  ),  ),  )] 

]

i.e a mixture of integers and mathematical characters. What I want to do is convert this into a series of strings in a 1D array like:

[
(1+2),
(1+2),
(1+2),
(1+2),
(1+2)
]

Is there a way to do this with join?

Answer 1

You could use transpose, and then join the elements of the transposed array (I have modified the numbers to clearly show what is happening):

# edited to add a transpose with map, thank you @Mladen
# edited to get rid of <<'s, thank you @tokland

# assumption: 
a = [ ['(', '(', '(', '(', '('],
      [1.1, 1.2, 1.3, 1.4, 1.5],
      ['+', '+', '+', '+', '+'],
      [2.1, 2.2, 2.3, 2.4, 2.5],
      [')', ')', ')', ')', ')'] ]

# transpose:
b = []
a.transpose.each { |c| b.push c.join }

# or, transpose with map:
b = a.transpose.map { |c| c.join }

# test:
puts b.inspect

Which has as an output:

["(1.1+2.1)", "(1.2+2.2)", "(1.3+2.3)", "(1.4+2.4)", "(1.5+2.5)"]