CODEWITHSUNDEEP
rubystring
Alex
Alex

Reputation: 13

While loop through a string in Ruby

I am entering "901000" as an argument to the following method, and I expect it to remove the last three zeros and return "901".

def zeros(x)
    str = x.to_s
    i = str.length-1
    while str[i] == "0"
        str = str.delete(str[i])
        i = i-1
    end
    return str
end

But it returns "91" instead. I cannot understand why my code does not work. Can someone help please?

Upvotes: 1

Views: 728

Answers (1)

sawa
sawa

Reputation: 168111

At first, str is "901000", i = str.length-1 is 5, and str[i] is "0". Hence,

str = str.delete(str[i])

is equivalent to

str = "901000".delete("0")

That gives you "91".

Then, by i = i-1, i becomes 4, and str[i] (which is equivalent to "91"[4]) becomes nil, and str[i] == 0 (which is equivalent to nil == 0) becomes false. So the loop ends, returning the value str, which is "91".

To do what you want, some simple ways are:

"901000".sub(/0+\z/, "") # => "901"
"901000"[/.*?(?=0+\z)/] # => "901"

Upvotes: 3

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