Difference between is and ==

[bearophile]

Suliman:

> What difference between
> if ((x = stdin.readln().chomp) is "q")
> and
> if ((x = stdin.readln().chomp) == "q")
>
> ?

"is" performs a raw comparison of just the values, and the value 
of a string is its ptr and length field. While "==" compares 
their contents. So you want to use "==" here because you are 
interested to see if x contains the char 'q', because while their 
lengths could be equal, their ptr is surely different.

Bye,
bearophile