[Tutor] Hello Python Tutor - help please!

Wed Aug 22 18:15:57 CEST 2012

On Wed, Aug 22, 2012 at 11:33 AM, Cecilia Chavana-Bryant
<cecilia.chavana-bryant at ouce.ox.ac.uk> wrote:
> Hola Bill,
>
> Many thanks for your reply to my post, you seem to understand the
> predicament I am in very well. Unfortunately, I am currently working from
> home and do not have someone close by to help and this is why I came to this
> space. This is also why I asked for advise about interactive tutorials or
> video tutorials. I have found that I keep getting lost with the more
> traditional tutorials where you just read and then do exercises. Following
> the guide I mentioned on my initial post I got through the first 2 chapters
> but I found them quite hard going. I don't know if this makes me not a
> complete beginner but I certainly do not feel like I learned much from
> reading them. Maybe it is the trying to learn the "computer ecosystem" of
> terminal commands at the same time that is making this learning process so
> tough.
>
> With respect to my field data, during my 2 yrs of fieldwork I collected a
> large amount of data which is currently stored in excel files. My research
> involves remote sensing (data from Earth-observation satellites) and I work
> with data from the MODIS NASA satellite which monitors the health of forest
> canopies using reflectance data. My research is based in the Amazon. I have
> collected field data to monitor the leaf dynamics of canopy leaves during
> the dry season. Dry season is the time of year when many tropical trees
> change their old leaves for new ones. New leaves are more photosynthetically
> active (absorb more carbon from and release more oxygen into the atmosphere)
> so the leaf exchange of such a large forest region as the Amazon can have
> huge effects on regional and global carbon and water cycles and thus on
> global climate (apologies if I'm giving you loads more information than you
> need or requested?!). My data involves a large amount of data on leaf
> demography (we demographically surveyed more than 120,000 leaves), and
> thousands of morphological and reflectance measurements. I will have to
> reorganise this data and create a few easily manipulable datasets so I can
> sort data according to leaf age, canopy position, date, etc. Then I will
> have to do statistical analyses on the data. I will also have to model some
> of the data.
>
> Many thanks for taking the time to respond to my post so comprehensively and
> for your good wishes.
>
>
> Cecilia Chavana-Bryant
> DPhil Candidate - Remote sensing and tropical phenology
> Environmental Change Institute
> School of Geography and the Environment
> University of Oxford
> South Parks Road, Oxford, OX1 3QY
> Web: http://www.eci.ox.ac.uk/teaching/doctoral/chavanabryantcecilia.php
> Tel Direct: +44 (0)1865 275861
> Fax: +44 (0)1865 275885
> ________________________________
> From: William R. Wing (Bill Wing) [wrw at mac.com]
> Sent: 22 August 2012 15:17
> To: Cecilia Chavana-Bryant
> Cc: William R. Wing (Bill Wing)
> Subject: Re: [Tutor] Hello Python Tutor - help please!
>
> On Aug 22, 2012, at 6:10 AM, Cecilia Chavana-Bryant
> <cecilia.chavana-bryant at ouce.ox.ac.uk> wrote:
>
> Dear all,
>
> I am just returning to my doctoral studies after a 7-month medical leave and
> desperately trying to catch up for lost time. I am COMPLETELY new to
> programming, well, I did try learning C for 3 weeks 3 yrs ago (with very
> little success) but had to stop and then spent 2 years in the Amazon
> climbing trees (lots more enjoyable than learning to programme!) and
> collecting loads of field data that I now need to post-process and analyse.
> By the way, the 3 weeks I spent trying to learn C really ended up being
> spent trying to get to grips with using a terminal for the first time in my
> life.
>
>
> Could you say a few words about what the field data is, and how you hope to
> analyze it.  That is, are you headed in the direction of plotting species
> density on maps, or the time evolution of something, or doing statistics?
>
> Since getting back to work, I was advised to try learning Python instead of
> C as it is a much easier first language to learn. I have been trying, but
> again, to not great success. I started following "A Primer on Scientific
> programming with Python" but I kept getting lost and stuck, specially on the
> exercises. I have also been advised that I should not try to learn
> programming by following guides but by trying to write the programmes I need
> to analyse my data. Although I can understand the logic behind this last bit
> of advise (it gives context and direction to the learning process) I have
> also gotten stuck trying this approach as "I do not know how to programme!".
> Thus, I was hoping that some of you can remember how you got started and
> point me towards any really good interactive learning guides/materials
> and/or have a good learning strategy for a complete beginner. I have
> searched the web and was overwhelmed by choice of tutorials and guides. I
> have skimmed through a couple of tutorials but then fail to see how all that
> relates to my own work and I get stuck with what seems like basic important
> concepts so I don't progress. I then think I should try to make some
> progress with my own data analysing and go back to trying to learn to write
> a programme for my specific needs and get stuck again because this requires
> more advanced skills then the basic programming concepts I have been reading
> about on the learning guides. So, I am now feeling VERY frustrated and have
> no idea what on Earth I am doing! Can anyone please offer guidance in my
> learning process? I don't know how and what I should be spending my time
> learning first and/or if I should focus my learning towards the skill areas
> I will require to write my specific programmes, although I have no idea what
> these are. I would like advise on finding some really good interactive(let
> you know if your solution to an exercise is correct or not) and or video
> tutorials that give you feedback on the solutions you write to exercises.
>
> Many thanks in advance for all your help, it will be much appreciated!
>
>
>
> I think there are three problems here, and you are (for better or worse)
> attempting to tackle all three at once.  First, and foremost, "leaning to
> program" really means learning a particular way of thinking about a problem,
> and how to decompose it into a sequence of steps.  Most programmers learned
> that way of thinking about problems so early in their careers they've
> forgotten it[*].  In parallel with that, you are trying to learn and
> understand the whole computer "ecosystem" of terminal commands, reading and
> writing files (and structuring their contents), data types, utilities, and
> libraries.  Finally, there is the actual work of writing the specific
> programs necessary to deal with your data.  Under any circumstances,
> tackling these all at once (or even in series) would be a heroic
> undertaking, doing so under the pressure of writing your thesis is (and this
> is purely my personal opinion) going to require that you have someone there
> at your elbow to help you through the first few days (weeks) of learning,
> particularly to help you with the first two issues I mention above.
>
> I agree that Python is an excellent choice for a first language.  It allows
> instant testing, provides immediate feedback with very good error messages,
> and is very flexible.
>
> [*] Years ago, I agreed to help a co-worker "learn to program".  This was
> back in the days of FORTRAN-IV, McCracken, and computers on which 64
> thousand memory locations was a lot of memory.  I showed him how to use an
> editor to enter code, loaned him my copy of McCracken, explained on a
> blackboard how the various statements worked and how FORTRAN directed logic
> flow and could do arithmetic.  Then, as an initial exercise, I asked him to
> write a program to find prime numbers.  This is a very standard initial
> exercise in programming, and forces the student to think through how you
> would test a number to find out if it is prime.  If it is, print it out and
> if it isn't, go on to the next one.  HIS solution was to define a square
> array indexed with the integers on each side.  The cells of that array were
> the products of the integers, and he intended to then scan that square
> looking for the numbers that DIDN'T exist in it.  Those would be prime.  So,
> note that there is nothing logically wrong with this solution.  But in a
> practical world (particularly a world with very limited memory) it stops
> working at a fairly small value of prime numbers.  The point I'm trying to
> make (in far too long winded a fashion) is that "learning to program"
> involves a lot more than just rote leaning of syntax.
>
> We all wish you the VERY best of luck.  We will give you all the help we
> can, but I do hope you have someone close by.
>
> Good luck,
> Bill
>
>
>
> Cecilia Chavana-Bryant
> DPhil Candidate - Remote sensing and tropical phenology
> Environmental Change Institute
> School of Geography and the Environment
> University of Oxford
> South Parks Road, Oxford, OX1 3QY
> Web: http://www.eci.ox.ac.uk/teaching/doctoral/chavanabryantcecilia.php
> Tel Direct: +44 (0)1865 275861
> Fax: +44 (0)1865 275885
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Some people have had a good experience with this:
http://learnpythonthehardway.org/book/

It starts out very basic, requiring you to type in very small learning
moments, then shifts gears and advances


-- 
Joel Goldstick