How to detect if a string contains any funny characters from non English alphabets


I have a specific problem that maybe you can help with.

Given an input of string (up to 1000 characters), how do I detect if
the string is not written in “Roman Alphabets (A-Z)”, and by that I mean
that the string maybe in Chinese, Korean, or contain non-standard
English or western language alphabets, etc.

I just need a function that will return “True” or “False”.

Thanks in advance!


Well I looked at the API and thought that str.each_char {} might
work, but it’s not recognized in my version of Ruby (1.8.6 on Ubuntu)
so that seems to be a dead end. Here’s an ugly hack that works though:

def nonroman_test(str)
if nonroman(str) then
puts “#{str} has nonroman characters!”
puts “#{str} does not have nonroman characters!”

def nonroman (str)
(/^[\w\[email protected]#$%^\&()][,.?]$/ =~ str) == nil


nonroman(str) return true if the string contains any characters
besides letters, digits, whitespace, and the following: [email protected]#$%^&*()

You can alter the regular expression to change what is allows. Just
add any additional allowed characters before the final ] on the line
in nonroman(). Some characters may need to have a \ in front of them
to work.

Hope that helps!

David Alves

Hi –

On Tue, 22 Jul 2008, Dave wrote:

Well I looked at the API and thought that str.each_char {} might
work, but it’s not recognized in my version of Ruby (1.8.6 on Ubuntu)

Right now, the latest release of Ruby 1.8 is 1.8.7, which is basically
a backport of many features from 1.9. The result is that the current
API docs have a very 1.9-ish flavor, and you’ll see lots of things in
there that don’t exist in 1.8.6. It’s potentially kind of confusing
since many of us are still using 1.8.6, and 1.8.7 sounds like it will
be more like 1.8.6 than like 1.9. But you can still get the 1.8.6 docs

def nonroman (str)
(/^[\w\[email protected]#$%^\&()][,.?]$/ =~ str) == nil

A better way might be:

def nonroman(str)
str =~ /[^\w\s!..]/

(with whatever regex you use). This way, you’re testing for the first
non-roman character, rather than testing all the characters. It
returns nil or a digit; change as needed if you specifically need

Also, don’t forget that ^ and $ are line anchors, not string anchors.


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