CODEWITHSUNDEEP
rubystringgsub
Dla Lols
Dla Lols

Reputation: 11

How to use gsubstitution with more letters

I've printed the code, wit ruby

string = "hahahah"
pring string.gsub("a","b")

How do I add more letter replacements into gsub?

string.gsub("a","b")("h","l") and string.gsub("a","b";"h","l")

didnt work...

*update I have tried this too but without any success .

letters = {
"a" => "l"
"b" => "n"
...
"z" => "f"
}
string = "hahahah"
print string.gsub(\/w\,letters)

Upvotes: 1

Views: 53

Answers (1)

BobRodes
BobRodes

Reputation: 6165

You're overcomplicating. As with most method calls in Ruby, you can simply chain #gsub calls together, one after the other:

str = 'adfh'
print str.gsub("a","b").gsub("h","l") #=> 'bdfl'

What you're doing here is applying the second #gsub to the result of the first one.

Of course, that gets a bit long-winded if you do too many of them. So, when you find yourself stringing too many together, you'll want to look for a regex solution. Rubular is a great place to tinker with them.

The way to use your hash trick with #gsub and a regex expression is to provide a hash for all possible matches. This has the same result as the two #gsub calls:

print str.gsub(/[ah]/, {'a'=>'b', 'h'=>'l'}) #=> 'bdfl'

The regex matches either a or h (/[ah]/), and the hash is saying what to substitute for each of them.

All that said, str.tr('ah', 'bl') is the simplest way to solve your problem as specified, as some commenters have mentioned, so long as you are working with single letters. If you need to work with two or more characters per substitution, you'll need to use #gsub.

Upvotes: 1

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