Ruby uppercase only specified range

Introduction

This will be a learning note.

Two space-separated integers and a string are entered. The substring of the range of two integers is output in uppercase.

Input example 1
2 6
this is a pen

Output example 1
tHIS Is a pen

Input example 2
2 6
Welcome to the paiza! I`m studying ruby!

Output example 2
WELCOMe to the paiza! I`m studying ruby!

Source code

nums = gets.chomp.split(' ')
str = gets.chomp

(1..(str.size)).each do |i|
  if nums[0].to_i <= i && i <= nums[1].to_i
    print str[i - 1].upcase
  else
    print str[i - 1]
  end
end

Commentary

nums = gets.chomp.split(' ')
str = gets.chomp

gets method: Receives input as a "character string" line by line. chomp method: Removes line breaks in character strings. split method: Splits a character string into an array.

(1..(str.size)).each do |i|

From 1 to the size method, assign the character string of str to the i variable and repeat one by one. (13 times)

if nums[0].to_i <= i && i <= nums[1].to_i
    print str[i - 1].upcase
  else
    print str[i - 1]
  end

In the if statement, i (array number) is larger than nums [0](2 in Example 1) and i is larger than nums [1](6 in Example 1). If (array number) is small, convert it to uppercase with ʻupcase`.

Otherwise, output as it is.

Finally

The explanation may be a little difficult to understand. I would appreciate it if you could point out any mistakes.