ruby - can't concatenate array elements into a string? - ruby

Question

For personal homework I am trying out a digital clock program to display 'big' numbers.
A ruby program that has parts of the clock that come from strings stored in an array and then a routine (not yet fully written) that can display any numbers as 'big numbers'.
This is to help me learn more about manipulating hashes and iterating through arrays, concatenating string, etc.
I am stuck right now with this:
all_nums=''
(0..3).each do |num|
all_nums+= (line_parts[num][0].values).to_s
#puts line_parts[num][0].values
end
puts all_nums
because I am getting back array elements that I can't convert to strings, i.e.
ruby digital_clock,rb
[" == "]["| | "]["| | "][" == "]
but when I just puts them (commented out 3rd line from the bottom) it is OK but, I get strings, i.e.
ruby digital_clock.rb
==
| |
| |
==
I want to be able to build up the string (big 0 in this case) but I can only puts out the pieces and I've been unable to assign them to a variable and print it. How could I do that?
The full program is:
top= ' == | == == | | == | == == == '
top_middle= '| | | __| __| |__| |__ |__ | |__| |__|'
bottom_middle='| | | | | | | | | | | | |'
bottom= ' == | == == | == == | == |'
number_parts=[{},{},{},{},{},{},{},{},{},{}]
line_parts=[[],[],[],[]]
['top','top_middle','bottom_middle','bottom'].each_with_index do |one_line, i|
number_parts=[{},{},{},{},{},{},{},{},{},{}]
(0..9).each do |the_num|
number_parts[the_num] = {one_line.to_sym => eval(one_line)[the_num*5,5].to_s}
end
line_parts[i]= number_parts
end
all_nums=''
(0..3).each do |num|
all_nums+= (line_parts[num][0].values).to_s
#puts line_parts[num][0].values
end
puts all_nums

Answer 1

I think this will fix your immediate problem -- namely, printing a big "0".
all_nums = []
(0..3).each do |num|
all_nums.push(line_parts[num][0].values)
end
puts all_nums.join("\n")
A better way to do that would be with map:
all_nums = (0..3).map { |num| line_parts[num][0].values }
puts all_nums.join("\n")
Another issue: you don't need to use eval. In fact, one almost never needs to use eval.
# Use variables rather than the strings 'top', 'top_middle', etc.
[top,top_middle,bottom_middle,bottom].each_with_index do |one_line, i|
...
# Then the eval() is unnecessary.
number_parts[the_num] = {one_line.to_sym => one_line[the_num*5,5]}
....
But you can really simplify the code along the following lines:
# Use an array, not a set of specifically named variables.
# This makes it a lot easier to iterate over the data.
rows = [
' -- | -- -- | | -- | -- -- -- ',
' | | | __| __| |__| |__ |__ | |__| |__|',
' | | | | | | | | | | | | |',
' -- | -- -- | -- -- | -- |',
]
# Create an array-of-arrays.
# num_parts[NUMBER] = [an array of four strings]
width = 5
num_parts = (0..9).map { |n| rows.map { |r| r[n * width, width] } }
# Inspect.
num_parts.each do |np|
puts
puts np.join("\n")
end
You might also take a look at the Unix command called banner, which will inspire you to make the numbers EVEN BIGGER. That would allow you to start adding curves and other design touches.