Im trying to eval this function and appears
this error
TypeError - no implicit conversion of Fixnum into String
eval("File.open('nagai.txt', 'a+') do |f| \n f. puts parts[" + params[:salutation].to_i + "] \n end")
how I could solve
1 Answer
This code is extremely risky and I can't see a reason for doing this in the first place. Remove the eval and you get this very ordinary code:
File.open('nagai.txt', 'a+') do |f|
f.puts parts[params[:salutation]]
end
The error comes from trying to concatenate a Fixnum/Integer to a String in the process of constructing the code you then eval. This code is invalid and yields the same error:
"1" + 1
Ruby isn't like other languages such as JavaScript, PHP or Perl which arbitrarily convert integers to strings and vice-versa. There's a hard separation between the two and any conversion must be specified with things like .to_s or .to_i.
That fixed version should be equivalent. If you need to defer this to some later point in time, you can write a method:
def write_nagai(params)
File.open('nagai.txt', 'a+') do |f|
f.puts parts[params[:salutation]]
end
end
2 Comments
Aleksei Matiushkin
I believe it’s vice versa:
params[:salutation] is a string instance passed to an array expecting an integer index.
tadman
@mudasobwa Now that I read this code I realize it's a classic case of trying to concatenate string + integer + string which always generates an error. The hash is a red-herring. The strange
eval layer adds a lot of confusion. Thanks for pointing out that I didn't have it pinned down right though.
eval()