String comparison

ruby-talk
1

Hi,

I have a class containing a string as an instance variable and I have a local variable containing a string.

I compare these two strings with '==' and with the .eql? method:

···

###################################

obj.text = "hello world"
localtext = "hello world"

if obj.text == localtext
then
  # do something
end

###################################

The condition never became true in my program. Thus I added some debug output. This is the the debugging code:

if not obj.text == localtext
then
  print "\"#{obj.text}\" is not equal \"localtext\"\n"
end

This is, what it gave me:

"hello world" is not equal "hello world"

It's not worth trying the example above, since it's not the actual code. The actual code in my project is much more complex, that's why I used this example to discribe my problem.

Fact is that when the string comparison does not succeed I get an output like

"hello world" is not equal "hello "world"

Now it's your turn... What could cause this behaviour?

thanks and greets

Boris

2

hello,

the below code displays 'equal' on my machine:

s0 = "hello world"
s1 = "hello world"
puts 'equal' if s0 == s1

konstantin

3

You have real diff here:

"hello world" is not equal "hello "world"

I tried this code.
Behaves as expected, prints equal.

class Obj
  attr_accessor :text
end

def test
  obj=Obj.new
  obj.text="world"
  localtext="world"
  if obj.text == localtext then
    print "equal\n"
  else
    print "not equal\n"
  end
end

test

Isolate the problem, and wrap it in a test/unit. Then I can take a
closer look.

Christer

···

--
Posted via http://www.ruby-forum.com/\.

4

Just to remove any precedence weirdness, does this behave differently
from your failing code?
puts %Q[#{obj.text} differs from #{localtext}] unless obj.text == localtext

···

On 12/14/05, Boris Glawe <boris@boris-glawe.de> wrote:

if not obj.text == localtext
then
        print "\"#{obj.text}\" is not equal \"localtext\"\n"
end

This is, what it gave me:

"hello world" is not equal "hello world"

5

You might check to see that obj.text.class is the same as obj.text.class.
Also check the sizes of both. I've been caught by \n which doesn't show up.

Boris Glawe wrote:

···

Hi,

I have a class containing a string as an instance variable and I have a local variable containing a string.

I compare these two strings with '==' and with the .eql? method:

###################################

obj.text = "hello world"
localtext = "hello world"

if obj.text == localtext
then
    # do something
end

###################################

The condition never became true in my program. Thus I added some debug output. This is the the debugging code:

if not obj.text == localtext
then
    print "\"#{obj.text}\" is not equal \"localtext\"\n"
end

This is, what it gave me:

"hello world" is not equal "hello world"

It's not worth trying the example above, since it's not the actual code. The actual code in my project is much more complex, that's why I used this example to discribe my problem.

Fact is that when the string comparison does not succeed I get an output like

"hello world" is not equal "hello "world"

Now it's your turn... What could cause this behaviour?

thanks and greets

Boris

6

Isolate the problem, and wrap it in a test/unit. Then I can take a closer look.

The problem was a whitespace, which I did not see. I actually wrapped the output in apostrophs in order to see whitespaces. Since I am programming with cgi, I see the output in the browser window, which prints whitespaces very small.

Anyway thanks for the help!!

greets Boris

7

you can run your cgi script from a command line thus: 'ruby script.cgi'
just set REQUEST_URI environment variable to set the url.

konstantin