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I have a string in Ruby on which I'm calling the strip method to remove the leading and trailing whitespace. e.g.
s = "12345 " s.strip However if the string is empty nil I get the following error.
NoMethodError: undefined method `strip' for nil:NilClass I'm using Ruby 1.9 so whats the easiest way to check if the value is nil before calling the strip method?
Update:
I tried this on an element in an array but got the same problem:
data[2][1][6].nil? ? data[2][1][6] : data[2][1][6].split(":")[1].strip 
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In Ruby, you can check if an object is nil, just by calling the nil? on the object... even if the object is nil. That's quite logical if you think about it :) Side note : in Ruby, by convention, every method that ends with a question mark is designed to return a boolean (true or false).
In Ruby, nil is a special value that denotes the absence of any value. Nil is an object of NilClass. nil is Ruby's way of referring to nothing or void. Ruby also provide a nil?
nil is an Object, NULL is a memory pointer Sadly, when this happens, Ruby developers are confusing a simple little Ruby object for something that's usually radically different in “blub” language. Often, this other thing is a memory pointer, sometimes called NULL, which traditionally has the value 0.
No, you can't return nothing. In ruby you always return something (even if it's just nil ) - no way around that. That said, nil is supposed to represent the concept of 'nothing'.
Ruby 2.3.0 added a safe navigation operator (&.) that checks for nil before calling a method.
s&.strip If s is nil, this expressions returns nil instead of raising NoMethodError.
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