Sorry for the vague title, couldnt think of a brief way to explain exactly what i mean. I have backtested systems before on programs like Tradestation and CQG where you have everything in one place. Indicators, charts, an area to write the code etc. The code is pretty much picking an indicator and saying "buy above MA" and the software knows what "buy" "above" and "MA" all mean. But with a coding language such as Python you have an empty white page to start writing and nothing else and doesnt seem to have much vocabulary unless you build it all from scratch. I dont understand where you get data, where you get the charts etc? Say for example i knew how to code Python to a high level and wanted to test trading systems with accurate high level data (so im talking whats going on in the order book, volume available on the bid and ask etc) where would you get that from? Can it just be bought as a file? Is there an online server you tap into? Just in laymans terms if you have the language how do you then build a system with it? Are there programs that look like CQG with all the indicators and charts etc? Hope that make sense, its just at the moment i am learning python and getting pretty bored of getting it to print "hello world" and making text go upper and lower case. Dont see how i could apply anything to trading.