Also, one shouldn't ignore the practical advantages of a batteries-included language (like Python) for enabling you to do things.
For example, if one wants to do some transformation of a spreadsheet which might be tricky or annoying to do in Excel/LibreOffice, one can just import csv and you've got a complete CSV file reader. Similarly, it's an import and 2 function calls to get a file off the internet.
Similarly, it's an import and 2 function calls to get a file off the internet.
I only count one function call:
import requests
f = requests.get(my_url).text
The built-in urllib and urllib2 modules can do this too, but they're a disaster that should be buried in the ground. The general consensus is that requests is the Right Thing. You have to install it, but that should be easy with the pip package manager:
$ pip install requests
By the way, I agree with the recommendation of Python. It's a very easy language to get started with, and it's practical for a...
Learning to program in a given language requires a non-trivial amount of time. This seems to be agreed upon as a good use of LessWrongers' time.
Each language may be more useful than others for particular purposes. However, like e.g. the choice of donation to a particular charity, we shouldn't expect the trade-offs of focusing on one versus another not to exist.
Suppose I know nothing about programming... And I want to make a choice about what language to pick up beyond merely what sounds cool at the time. In short I would want to spend my five minutes on the problem before jumping to a solution.
As an example of the dilemma, if I spend my time learning Scheme or Lisp, I will gain a particular kind of skill. It won't be a very directly marketable one, but it could (in theory) make me a better programmer. "Code as lists" is a powerful perspective -- and Eric S. Raymond recommends learning Lisp for this reason.
Forth (or any similar concatenative language) presents a different yet similarly powerful perspective, one which encourages extreme factorization and use of small well-considered definitions of words for frequently reused concepts.
Python encourages object oriented thinking and explicit declaration. Ruby is object oriented and complexity-hiding to the point of being almost magical.
C teaches functions and varying abstraction levels. Javascript is more about the high level abstractions.
If a newbie programmer focuses on any of these they will come out of it a different kind of programmer. If a competent programmer avoids one of these things they will avoid different kinds of costs as well as different kinds of benefits.
Is it better to focus on one path, avoiding contamination from others?
Is it better to explore several simultaneously, to make sure you don't miss the best parts?
Which one results in converting time to dollars the most quickly?
Which one most reliably converts you to a higher value programmer over a longer period of time?
What other caveats are there?