Sum of first part of string in an array of strings

Question

I have an array of strings from which I need to extract the first words, convert them to integers and get the their sum.

Example:

["5 Apple", "5 Orange", "15 Grapes"]

Expected output => 25

My attempt:

["5","5","15"].map(&:to_i).sum

Answer 1

I found the answer from your question.

["5 Apple", "5 Orange", "15 Grapes"].map(&:to_i).sum

In array if any integer convertable value is present then it will automatically convert into integer.

Answer 2

Map with #split :

["5 Apple", "5 Orange", "15 Grapes"].map{|s| s.split.first.to_i }.sum
=> 25

Answer 3

String#to_i looks for digits at the start of the string and converts them to integers:

'Foo'.to_i   # => 0
'5 Bar'.to_i # => 5
'Baz 5'.to_i # => 0 

Hence just sum the result of to_i :

["5 Apple", "5 Orange", "15 Grapes"].sum(&:to_i) # => 25

Answer 4

["5 Apple", "5 Orange", "15 Grapes"].sum { |w| w.split(' ').first.to_i }

会做到的。

Answer 5

I see this is now the most popular question in the Ruby section, so here's another way:

["5 Apple", "5 Orange", "15 Grapes"].reduce(0) {|sum,n| sum + n.to_i}

Or as suggested by @EricDuminil, just:

["5 Apple", "5 Orange", "15 Grapes"].sum(&:to_i)