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goals do
goal "Understand when to use strings"
goal "Learn how to combine strings"
goal "Learn about string interpolation"
end
step do
irb <<IRB
'a string in single quotes'
"a string in double quotes"
IRB
message 'A string is a series of characters. Strings can be created using either single or double quotes.'
message 'These strings weren\'t saved into a variable. What happens to data not saved into a variable?'
message 'What happens if you start a string with one kind of quote and end with another? How can you fix it?'
end
step do
irb <<IRB
'Hello, ' + 'Jane'
'apples' * 3
IRB
message 'Strings can be added to each other or multipled by numbers. What does this do?'
end
step do
irb <<'IRB'
name = 'Jane'
"Hello #{name}"
IRB
message '(the `{}` characters are generally called **curly braces**)'
message 'This is called string interpolation. String interpolation lets you embed a Ruby statement in another string. It only works with double quotes: what happens when you try the same thing with single quotes?'
irb <<'IRB'
"Two plus two is #{2 + 2}"
IRB
message 'The code in the curly braces can be any valid Ruby statement. Try putting various things in the curly brackets to see what works and what doesn\'t.'
end
tip <<-'MD'
# Concatenation vs. Interpolation
first = "Joe"
last = "Smith"
`+` does *concatenation*
full = first + " " + last
`#{}` does *interpolation*
full = "#{first} #{last}"
MD
step do
message "Try out some of these String methods."
irb <<-IRB
'I have many characters'.length
'forwards'.reverse
'jane smith'.upcase
'a plain old sentence'.delete('aeiou')
IRB
message "<a href='/ruby/datatypes'>Recall</a> that you can see what methods
are available for an object by calling `.methods` on it."
irb "'some string'.methods"
end
explanation do
message "Strings are a key way to present information in your programs. Since a human will probably be reading the output of your program eventually, and humans speak words rather than numbers, you will often want to use strings."
message 'A not at all complete summary of methods on String:'
table class: 'bordered' do
tr do
td 'length'
td 'how long is this string (characters)'
end
tr do
td 'reverse'
td 'return same string, reversed'
end
tr do
td 'upcase'
td 'return same string, IN UPPER CASE'
end
tr do
td 'delete([another string])'
td 'delete all characters in the second string from the first'
end
tr do
td 'methods'
td 'get the names of all methods you can perform on string'
end
end
end
further_reading do
a "Ruby's documentation for String", href: 'http://ruby-doc.org/core-2.2.0/String.html'
end
next_step 'input_and_output'