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I'm new to Ruby, and have been working my way through Mr Neighborly's Humble Little Ruby Guide. There have been a few typos in the code examples along the way, but I've always managed to work out what's wrong and subsequently fix it - until now!
This is really basic, but I can't get the following example to work on Mac OS X (Snow Leopard):
gone = "Got gone fool!"
puts "Original: " + gone
gone.delete!("o", "r-v")
puts "deleted: " + gone
Output I'm expecting is:
Original: Got gone fool!
deleted: G gne fl!
Output I actually get is:
Original: Got gone fool!
deleted: Got gone fool!
The delete! method doesn't seem to have had any effect.
Can anyone shed any light on what's going wrong here? :-\
785
In Ruby, we can permanently delete characters from a string by using the string. delete method. It returns a new string with the specified characters removed.
The chop method is used to remove the last character of a string in Ruby. If the string ends with \r\n , it will remove both the separators. If an empty string calls this method, then an empty string is returned. We can call the chop method on a string twice.
string. gsub!( /\d+/,"") will remove all numbers from the string.
Ruby allows part of a string to be modified through the use of the []= method. To use this method, simply pass through the string of characters to be replaced to the method and assign the new string.
The String.delete method (Documented here) treats its arguments as arrays and then deletes characters based upon the intersection of its arrays.
The intersection of 2 arrays is all characters that are common to both arrays. So your original delete of gone.delete!("o", "r-v") would become
gone.delete ['o'] & ['r','s','t','u','v']
There are no characters present in both arrays so the deletion would get an empty array, hence no characters are deleted.
127
I changed
gone.delete!("o", "r-v")
to
gone.delete!("or-v")
and it works fine.
43
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