Covered in this episode:
- String Literals
- String Expressions
- String Methods
- Regular Expressions
- Getting User Input (gets)
Transcript:
Hello Everyone and Welcome to Programming With Ruby Episode 6,
Strings. I’m Tyler, your presenter. This is brought to you by
manwithcode.com
In this episode I will be telling you what string literals are. I will
show you expressions you can use with strings, which are similar but
still different than expressions with numbers. I will show you useful
methods strings have. I will show you how to use regular
expressions. Finally I will teach you how to get input from the
user.
On to the Code!
String Literals
According to wikipedia, string literals are the representation of a
string value within the source code of a computer program. For
example:
puts "Hello World" # Hello World is the string literal
String Expressons
The only string expressions are the plus and multiplication sign. The
plus sign connects strings together, the multiplication sign repeats a
string a certain number of times.
Let me show you how it works:
"Hello " + "World!" #=> "Hello World!" "Hello " * 3 #=> "Hello Hello Hello"
String Methods
Here are some useful String methods:
empty? tells you if you are dealing with an empty string
length tells you how long a string is
each_char lets you iterate over each character
capitalize capitalizes the first character
upcase makes all characters upper case
downcase makes all characters lower case
Regular Expressions
Regular expressions are a way to match elements in other strings. It
is easier to show you than to describe to you, so here we go!
The simplest is substitution:
"Hello World".sub("Hello", "Goodbye")
#=> "Goodbye World"
But if you have more than one hello:
"Hello Hello Hello".sub("Hello", "Goodbye")
#=> "Goodbye Hello Hello"
This happens because the sub method only replaces the first occurrence
of “Hello”. The gsub method fixes this:
"Hello Hello Hello".gsub("Hello", "Goodbye")
#=> "Goodbye Goodbye Goodbye"
What if you want to manipulate parts of a string using regular
expressions. The scan method is what you want!
# /n means new line
"Who are you".scan(/../) { |x| puts x }
#=> Wh\no \nar\ne \nyo
# With no whitespace:
"Who are you".scan(/\w\w/) { |x| puts x }
#=> Wh/nar/nyo
Regular Expressions are a vast topic that I can’t completely cover
here, so do a Google search to find out more.
Getting User Input
You can get user input with the “gets” method:
a = gets # The user inputs: I like pie puts a #=> "I like pie"
That wraps it up for todays episode.
Don’t forget to donate, the link is to the right of this video
If you have any questions or comments, leave a comment on this page or
email me at tyler@manwithcode.com
Bye!