Each_char, each_line

Suppose we want to iterate over the characters or lines in a string. We could use a for-loop, with logical branches, but iterators can also be used.

Iterator notes

In Ruby, we often prefer to use iterators to keep code more graceful, reliable and compact. For iterating over strings, we use each_char and each_line.

Each_char example

This iterator loops over each character in a string. With each_char, we introduce an iteration variable. This is a character in the string.

value = "ruby"

# Loop over each character with each_char.
value.each_char do |c|
    # Write char.
    puts c
end
r
u
b
y

Each_line example

This iterator loops over all the lines in a string. If your input string has newlines, each_line will return separated strings.

# String literal with 2 newline characters.
data = "Ruby\nPython\nPerl"

# Loop over lines with each_line.
data.each_line do |line|
    # Write line.
    puts line
end
Ruby
Python
Perl

Looping over strings is a common task in Ruby (and most other programming languages). Iterators can make this task clearer and easier to maintain.