IMP1 Ruby Tutorial

by **IMP1** Sun Jun 06, 2010 9:55 am

First off, download the Ruby Installer. It'll allow you to try out ruby by yourself.

Ruby Tutorial II - Strings

Things to know:
The alphabet?

How long is a piece of string? Ruby knows. Do you?

A string is a group of text. Pretty simple, no? Here are a couple of examples:

Code:: "hi" 'This uses inverted commas' "This uses speech marks"

There's no real difference between '' and "", each coder has their preferences.

Now, take a look at this:

Code:: 'Hi. I'm IMP1'

The problem here, is Ruby mistakes the apostrophe for the end of the string. And Ruby's not gonna recognise the command m IMP1.
Now, we wouldn't have this problem with speech marks, but we could also use the escape character (\). And now it'd look like this:

Code:: 'Hi. I\'m IMP1'

Here's another example of the escape character:
Input:

Code:: "So you said \"Shut up\"! and I'm not even talking!" "BackSlash!! \\" "Yes\\No" "Yes\No"

Note you don't need to escape the ' because I used "".
Output:

Code:: "So you said "Shut up"! and I'm not even talking!" "BackSlash!! \" "Yes\No" "Yes\No"

Two backslashes cancel out the escape powers, leaving behind a single backslash. The last two are the same as a \ won't cancel out a d.

Now, just like numbers (not quite JUST like), strings can be added or multiplied!
Input

Code:: "Hi." + " I'm IMP1" "abc" + "def" + 'ghi' "nom " * 3 "lo" * 4

Note the space before I'm IMP. That's because otherwise it'd print Hi.I'm IMP1.
Output:

Code:: "Hi. I'm IMP1" "abcdefghi" "nom nom nom " "lolololo"

Bare in mind when multiplying that the left side is being repeated (right hand side) times.
You also can't add a string to a number. It doesn't make sense.
So these won't work:
Input:

Code:: 3 * "Nom " "Hi." * "I'm IMP1" 2 + '2' '2' + 2

And these will give the following errors:
Output:

Code:: TypeError: String can't be coerced into Fixnum TypeError: can't convert String into Integer TypeError: String can't be coerced into Fixnum TypeError: Fixnum can't convert into String

along with the location of the error in the script.

There are (clearly) differences between numbers and strings:
Input:

Code:: 2 + 2 "2" + "2" "2 + 2"

Will result in three completely different things
Output:

Code:: 4 "22" "2 + 2"

That seems like a lot to take in, so no homework today Razz

You can have the night off.

Good Hunting

NEXT TIME: Variables.

by yami Sun Jun 06, 2010 10:05 am

Once again, a brilliant tutorial

However, isn't there a difference between "" and ''
With "" you can use #{}!

by **IMP1** Sun Jun 06, 2010 10:49 am

Yeah, but i was saving #{} for variables Wink

by yami Sun Jun 06, 2010 11:06 am

oh ok

by alundra120 Sat Jul 31, 2010 9:25 am

There's no addition for strings. It's called concatenation.
Also, you can concatenate integers (numbers) and strings by converting the integer into a string using .to_s method.

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