`String` length

A string has a certain number of characters—this is its length. In Ruby we access the length property. We can use length in a for-loop or while-loop to access chars.

For most Ruby programs, using an iterator (like each_char) to access elements (like chars in a string) is best. But the length property, and a for-loop, can be used as well.

An example program

Let us review the length property. With the string "ABC" it returns the value 3—the string has 3 characters in it.

Detail We use a for-loop over the string to iterate over the chars in forward order. We access each char by its index.

Detail We can use a while-loop to iterate over the string in a reverse (backwards) order. We begin at length minus one.

# An input string.
value = "ABC"

# Display the string.
puts "VALUE:" << value
puts "LENGTH:" << String(value.length)

# Loop over characters in the string forwards.
for i in 0..value.length - 1
    puts "CHAR FORWARD:" << value[i]
end

# Loop over characters backwards.
temp = value.length - 1
while temp >= 0
    puts "CHAR BACKWARD:" <> value[temp]
    temp -= 1
endVALUE:ABC
LENGTH:3
CHAR FORWARD:A
CHAR FORWARD:B
CHAR FORWARD:C
CHAR BACKWARD:C
CHAR BACKWARD:B
CHAR BACKWARD:A

String length is important in Ruby. This high-level language hides a lot of the complexity of things. With iterators (like each_char) we hide complexity when looping over chars.

For the greatest level of control, though, for-loops (and similar loops) are sometimes needed. We can access adjacent chars, or modify the index as we go along.

String length

An example program

`String` length