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For 2021 - online Python 3 training - see ((here)).

Our plans were to retire in summer 2020 and see the world, but Coronavirus has lead us into a lot of lockdown programming in Python 3 and PHP 7.
We can now offer tailored online training - small groups, real tutors - works really well for groups of 4 to 14 delegates. Anywhere in the world; course language English.

Please ask about private 'maintenance' training for Python 2, Tcl, Perl, PHP, Lua, etc.
Setting up and using a dict in Python - simple first example

Here's a very short and easy example of the use of a dict in Python.

Set up a dict and fill it from a file (key value is 2nd field; value to be looked at is 7th)

  lookup = {}
  for record in open("railstats.txt","r"):
    fields = record.strip().split('\t')
    tlc = fields[1]
    name = fields[6]
    lookup[tlc] = name


You can't sort a dict - but you CAN sort a list of the keys

  codes = lookup.keys()
  codes.sort(lambda a,b: cmp(lookup[b],lookup[a]))


And you can then list the elements in the order of the list

  for code in codes:
    print code,lookup[code])


Complete code [here].

It's all very well looking at what a program does - but would you know how to decide how to write it like this? Our Pyton Programming courses will teach you. Follow our course schedule link if you'ld like to come - at the time of writing, I'm actually presenting a private course, there's another private course at the end of next month (February) and then there's a public course starting on 2nd March 2015, but the diary is updated if you've found this page on our archive, and we have dates available (from mid March) for private courses.
(written 2015-01-30)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
Y107 - Python - Dictionaries
  [103] Can't resist writing about Python - (2004-10-29)
  [955] Python collections - mutable and imutable - (2006-11-29)
  [1144] Python dictionary for quick look ups - (2007-04-12)
  [1145] Using a list of keys and a list of values to make a dictionary in Python - zip - (2007-04-13)
  [2368] Python - fresh examples of all the fundamentals - (2009-08-20)
  [2915] Looking up a value by key - associative arrays / Hashes / Dictionaries - (2010-08-11)
  [2986] Python dictionaries - reaching to new uses - (2010-10-05)
  [2994] Python - some common questions answered in code examples - (2010-10-10)
  [3464] Passing optional and named parameters to python methods - (2011-10-04)
  [3488] Python sets and frozensets - what are they? - (2011-10-20)
  [3554] Learning more about our web site - and learning how to learn about yours - (2011-12-17)
  [3555] Football league tables - under old and new point system. Python program. - (2011-12-18)
  [3662] Finding all the unique lines in a file, using Python or Perl - (2012-03-20)
  [3934] Multiple identical keys in a Python dict - yes, you can! - (2012-11-24)
  [4027] Collections in Python - list tuple dict and string. - (2013-03-04)
  [4029] Exception, Lambda, Generator, Slice, Dict - examples in one Python program - (2013-03-04)
  [4469] Sorting in Python 3 - and how it differs from Python 2 sorting - (2015-04-20)
  [4661] Unique word locator - Python dict example - (2016-03-06)
  [4668] Sorting a dict in Python - (2016-04-01)


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A good example of recursion - a real use in Python
Setting up and using a dict in Python - simple first example
Additional Python courses added to our schedule
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This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

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