Where to find practice problems for C, Python, Ruby and Scala

[sarvesh0303]

I have previously learned C and Python. I'm just starting out with Ruby and Scala. But I need to become more proficient in these languages, so could someone suggest good sources of problems/exercises in each of these languages
sources could include websites, books, etc.

 

[jedishrfu]

There may be some Ruby problems here at the listed websites:

http://iwanttolearnruby.com/

and for Scala:

http://aperiodic.net/phil/scala/s-99/