For 2023 (and 2024 ...) - we are now fully retired from IT training. We have made many, many friends over 25 years of teaching about Python, Tcl, Perl, PHP, Lua, Java, C and C++ - and MySQL, Linux and Solaris/SunOS too. Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own risk.
Lisa and I (Graham) now live in what was our training centre in Melksham - happy to meet with former delegates here - but do check ahead before coming round. We are far from inactive - rather, enjoying the times that we are retired but still healthy enough in mind and body to be active!
I am also active in many other area and still look after a lot of web sites - you can find an index ((here)) |
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)
Some other Articles
Binomial Coefficient (Pascal Triangle) objects in JavaJava -making sure you have the right versionsLocation, location location. And a chance of a giggle!A good example of recursion - a real use in PythonSetting up and using a dict in Python - simple first exampleAdditional Python courses added to our schedulePython - even named code blocks are objectsFixing damaged MySQL tables - Error 1712 and Error 2013Backup procedures - via backup serverWhich (virtual) host was visited? Tuning Apache log files, and Python analysis
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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.
Link to Ezine home page (for reading).
Link to Blogging home page (to add comments).
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