having issues adding an input to an array - arrays

Question

I have a problem that I think is asking me to have a user enter a input into a array. I am having difficulties understanding this and any help would be appreciated.
The problem is as follows:
Design a program that lets the user enter the total rainfall for each of 12 months into an array. The program should calculate and display the total rainfall for the year, the average monthly rainfall, and the months with the highest and lowest amounts.
Here is what I have wrote so far:
def get_rainfall(a, b)
rain_array = []
rain_array.push(a => b)
puts rain_array
end
get_rainfall('january', 300)

Answer 1

Thanks for updating the question C_B.
I think the slight issue you're having here is between hashes and arrays.
Your current method results in the following:
#=> [{"january"=>300}, {"february"=>...}]
This happens because when you call rain_array.push(a => b), you're pushing a hash to the array each time in a => b.
It seems to me you'd be better suited storing the whole things as a hash, perhaps:
hash = {}
def get_rainfall(hash, key, value)
hash[key] = value
puts hash
end
get_rainfall(hash, 'january', 300)
# {"january"=>300}
get_rainfall(hash, 'february', 200)
#{"january"=>300, "february"=>200}
Hash you add more entries, they will be stored under the month as the key, with the rainfall as the value.
Alternatively, you could also push an array of arrays - to tweak your current method:
rain_array = []
def get_rainfall(array, a, b)
array.push([a, b])
puts array
end
get_rainfall(rain_array, 'january', 300)
# january
# 300
get_rainfall(rain_array, 'february', 200)
# january
# 300
# february
# 200
You'll notice I'm pulling the declaration of the array or hash to store the values outside of the method; without this, you'll lose access to it as soon as the method has run.
Hope that helps - happy to expand if you've any questions or queries. Let me know how you get on.
One more update based on a further comment about getting user input. Try the following to get you started:
hash = {}
def get_rainfall(hash, month)
puts "Please enter value for #{month}"
hash[month] = gets.chomp
puts hash
end
get_rainfall(hash, 'january')

Answer 2

I'll write my answer in simple script form to not over complicate what is being asked here.
The minimal approach is to not worry about month names for now and simply collect a list (array) of 12 values to do the calculations with.
rainfall = 1.upto(12).map do |month_nr|
# `print` and `puts` are practically the same with the only difference being
# that `puts` adds a newline character to the string if it doesn't have one
# output the question to the user
print "enter the rainfall for month #{month_nr}: "
# get the input from the user and convert it into an integer
gets.to_i # output the rainfall
end
puts "the total rainfall is: #{rainfall.sum}"
puts "the average rainfall is: #{rainfall.sum / rainfall.size}"
puts "the highest rainfall is: #{rainfall.max}"
puts "the lowest rainfall is: #{rainfall.min}"
If you care about month names you can do the following:
# create an array of all months
months = %w[January February March April May June July August September October November December]
# ask the user for each moth the amount of rainfall
rainfall = months.map do |month_name|
print "enter the rainfall for month #{month_name}: "
[month_name, gets.to_i] # output both the month name and the rainfall provided
end
# convert [['January', 123], ['February', 456], ...]
# to { 'January' => 123, 'February' => 456, ... }
rainfall = rainfall.to_h
puts "the total rainfall is: #{rainfall.values.sum}"
puts "the average rainfall is: #{rainfall.values.sum / rainfall.size}"
# search the key with the highest value
puts "the month with the highest rainfall is: #{rainfall.key(rainfall.values.max)}"
# search the key with the lowest value
puts "the month with the lowest rainfall is: #{rainfall.key(rainfall.values.min)}"
If anything is unclear have a look at the reference of the thing it is you have difficulty with. If it's still unclear ask away in the comments.
references:
String interpolation ("1 + 1 = #{1 + 1}")
Integer#upto
Enumerable#map
Kernel#print output to standard output without appending newline
Kernel#gets read from standard input
String#to_i
Kernel#puts output to standard output while appending a newline character (unless already present)
Array#sum
Array#size
Array#max
Array#min
%w array of strings
Array#to_h convert array to a hash
Hash#values
Hash#key