[Tut] Fun with Strings

[Jordan L.]

Hey there.

Today I'm going to tell you about strings, and the fun things you can do with them. First, I'll try to explain what a string is by giving some examples and a quote from Google.

a collection of objects threaded on a single strand

I know the above quote is to do with things irl, but it's pretty much the same for Programming in Ruby. A string simply is a line of code with objects.

Example:
"This is a string"

1. Reversing a String.
There's a simple way to reverse a string, printing it out backwards in Ruby. For example, here is a code that gets the User's Number / Word and prints it out reversed.

Code:

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#! /usr/bin/env ruby

puts "Enter a Number or Word: "
num = gets.chomp
puts ""

puts "This is your number / word reversed: "
print num.reverse
puts ""

Really the only code in there you may or may not know is the num.reverse. Each time a User inputs sometihng it is automatically put into what we call strings. If we were to write:

Code:

puts "Enter a Number or Word: "
num = gets.chomp

print num.reverse

This is telling the program to Reverse the string that the user has entered. Say for example I write "Jordan" (Without the quotation marks) the program would recognise it as a string and print back "nodraJ".

Here's my example from the program I made:

jordan@ModernWarfare ~/Desktop/Ruby $ ruby strings.rb
Enter a Number or Word:
132

This is your number / word reversed:
231
jordan@ModernWarfare ~/Desktop/Ruby $
jordan@ModernWarfare ~/Desktop/Ruby $ ruby strings.rb
Enter a Number or Word:
Jordan

This is your number / word reversed:
nadroJ

2. Uppcasing and Lowercasing
Doing an upper case and a lower case is no different to doing a reverse. Just simple replace .reverse with either .upcase or .lowcase

Example:

Code:

puts "Enter a Word: "
num = gets.chomp

print num.upcase

Would make the output "JORDAN" or whatever your word was.
Where as:

Code:

puts "Enter a Word: "
num = gets.chomp

print num.lowcase

Would make the output from "JORDAN" to "jordan".

Thanks for reading my tut on fun with Strings, and I hope it helped you learn something.
Thanks!
-Jordan.

[Gaijin]

Nice one man, really good job!
Do you know something about Regular Expressions? Or how to replace parts of strings.

[Jordan L.]

I'm not sure about regular expressions, but I heard my mate is making a tut.
And for replacing in a strign, I think it's something using GSUB.
Like;

Code:

puts "Jordan".gsub("J", "X")

Would change J to X, making it Xordan.

I think that's how it works anyway, I don't know, try it. Mark (Wolskie) taught me that

[Gaijin]

I'm not sure about regular expressions, but I heard my mate is making a tut.
And for replacing in a strign, I think it's something using GSUB.
Like;

Code:

puts "Jordan".gsub("J", "X")

Would change J to X, making it Xordan.

I think that's how it works anyway, I don't know, try it. Mark (Wolskie) taught me that

Yes that worked, thanks!
And about the regular expressions, they work with the same function...

This code will convert every letter lowercase and uppercase from a-z with to the number 0...

Code:

puts "Jordan".gsub(/[A-Za-z]/, "0")

[Jordan L.]

Ah, I see what you mean.
Thanks for that, I didn't know that

So if I was to do:

Code:

puts "Jordan".gsub(/A]/, z)

Or sometihng like that, it would convert the capital J to a lowercase?

[Gaijin]

Ah, I see what you mean.
Thanks for that, I didn't know that

So if I was to do:

Code:

puts "Jordan".gsub(/A]/, z)

Or sometihng like that, it would convert the capital J to a lowercase?

You would use gsub(/[J]/, "j") to do that...
Your buddy has posted a tut, go and learn it

[Jordan L.]

Will do, thanks MoTU.

[Gaijin]

I'm back with a question....
How can I use defined variables inside of a String?

Something like this in PHP:

PHP Code:

echo $hello." World";
echo "{$hello} World";