data science

Open Data Science Conference
The Data Science Conference
AnacondaCON
QCon.ai
Re-Work

programming languages/javascript

JSConf - Conferences for the JavaScript Community

programming languages/python

List of Python Conferences & Workshops Worldwide
Official PyCon Website
List of Upcoming Python Conferences Worldwide

programming languages/r

R: Conferences

programming languages/ruby

RubyConf
RubyConf India
Deccan RubyConf, India