For 2023 - 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 Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own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)) |
Conditional operators in Python
Python does NOT support the ? and : condiitonal operator. Instead, the and and or keywords are lazy.
Look at this example which seeks out the longest line in a file and tells you how long it is:
fh = open("ac_20160516.xyz")
loli = 0
while True:
l = len(fh.readline())
if l == 0: break
loli = loli < l and l or loli
print loli
loli is the longest line to date as the file is parsed, with l being the length of each line. In the conditional line, loli is checked against l and the larger of the two is assignd back to loli. (written 2016-11-05, updated 2016-11-06)
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles Y103 - Python - Conditionals and Loops [299] What - no switch or case statement? - (2005-05-03) [353] Wimbledon Neck - (2005-06-20) [657] The ternary operator in Python - (2006-03-25) [668] Python - block insets help with documentation - (2006-04-04) [788] New - Conditional expressions in Python 2.5 - (2006-07-01) [835] Python - when to use the in operator - (2006-08-16) [909] Python is like a narrowboat - (2006-10-30) [1201] No switch in Python - (2007-05-23) [1477] Decisions - small ones, or big ones? - (2007-12-18) [1661] Equality, sameness and identity - Python - (2008-05-31) [1696] Saying NOT in Perl, PHP, Python, Lua ... - (2008-07-04) [2778] Learning to program in Python 2 ... and / or in Python 3 - (2010-05-24) [2899] Groupsave tickets - 3 or 4 train tickets for the price of 2 - (2010-08-02) [3083] Python - fresh examples from recent courses - (2010-12-11) [3200] How a for loop works Java, Perl and other languages - (2011-03-12) [3397] Does a for loop evaluate its end condition once, or on every iteration? - (2011-08-18) [3439] Python for loops - applying a temporary second name to the same object - (2011-09-14) [3558] Python or Lua - which should I use / learn? - (2011-12-21) [3620] Finding the total, average, minimum and maximum in a program - (2012-02-22) [3762] Learning to program - the if statement. Python. - (2012-06-12) [3895] Flowchart to program - learning to program with Well House - (2012-10-14) [4092] Identity in Python - (2013-05-17) [4210] If elif elif elif - multiway selection in Python - (2013-11-16) [4322] Learning to Program - the conditional statement (if) - (2014-11-21) [4323] Learning to program - Loop statements such as while - (2014-11-22) [4402] Finding sum, minimum, maximum and average in Python (and Ruby) - (2015-01-19) [4541] Setting up and tearing down with the Python with keyword - (2015-10-16) [4545] Method, Class, Module, Package - how to they relate in Python? - (2015-10-17) [4713] Equality (in Python) - (2016-10-30)
Some other Articles
Learning from travelling further afieldTransWilts Partner Update for Melksham Area BoardWriting Python 2 such that Python 3 is easyFrom and Import in Python - where is the module loaded from?Conditional operators in PythonEmbedding more complex code into a named blockWhen to check an object type - Python isinstance exampleCelebrating our diversity rather than discriminating for itNesting decoratorsDefining an object that is a modified standard type in Python
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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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