Home Accessibility Courses Twitter The Mouth Facebook Resources Site Map About Us Contact
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
  [4713] Equality (in Python) - (2016-10-30)
  [4545] Method, Class, Module, Package - how to they relate in Python? - (2015-10-17)
  [4541] Setting up and tearing down with the Python with keyword - (2015-10-16)
  [4402] Finding sum, minimum, maximum and average in Python (and Ruby) - (2015-01-19)
  [4323] Learning to program - Loop statements such as while - (2014-11-22)
  [4322] Learning to Program - the conditional statement (if) - (2014-11-21)
  [4210] If elif elif elif - multiway selection in Python - (2013-11-16)
  [4092] Identity in Python - (2013-05-17)
  [3895] Flowchart to program - learning to program with Well House - (2012-10-14)
  [3762] Learning to program - the if statement. Python. - (2012-06-12)
  [3620] Finding the total, average, minimum and maximum in a program - (2012-02-22)
  [3558] Python or Lua - which should I use / learn? - (2011-12-21)
  [3439] Python for loops - applying a temporary second name to the same object - (2011-09-14)
  [3397] Does a for loop evaluate its end condition once, or on every iteration? - (2011-08-18)
  [3200] How a for loop works Java, Perl and other languages - (2011-03-12)
  [3083] Python - fresh examples from recent courses - (2010-12-11)
  [2899] Groupsave tickets - 3 or 4 train tickets for the price of 2 - (2010-08-02)
  [2778] Learning to program in Python 2 ... and / or in Python 3 - (2010-05-24)
  [1696] Saying NOT in Perl, PHP, Python, Lua ... - (2008-07-04)
  [1661] Equality, sameness and identity - Python - (2008-05-31)
  [1477] Decisions - small ones, or big ones? - (2007-12-18)
  [1201] No switch in Python - (2007-05-23)
  [909] Python is like a narrowboat - (2006-10-30)
  [835] Python - when to use the in operator - (2006-08-16)
  [788] New - Conditional expressions in Python 2.5 - (2006-07-01)
  [668] Python - block insets help with documentation - (2006-04-04)
  [657] The ternary operator in Python - (2006-03-25)
  [353] Wimbledon Neck - (2005-06-20)
  [299] What - no switch or case statement? - (2005-05-03)


Back to
Embedding more complex code into a named block
Previous and next
or
Horse's mouth home
Forward to
From and Import in Python - where is the module loaded from?
Some other Articles
Learning from travelling further afield
TransWilts Partner Update for Melksham Area Board
Writing Python 2 such that Python 3 is easy
From and Import in Python - where is the module loaded from?
Conditional operators in Python
Embedding more complex code into a named block
When to check an object type - Python isinstance example
Celebrating our diversity rather than discriminating for it
Nesting decorators
Defining an object that is a modified standard type in Python
4724 posts, page by page
Link to page ... 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95 at 50 posts per page


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).

You can Add a comment or ranking to this page

© WELL HOUSE CONSULTANTS LTD., 2017: Well House Manor • 48 Spa Road • Melksham, Wiltshire • United Kingdom • SN12 7NY
PH: 01144 1225 708225 • FAX: 01144 1225 793803 • EMAIL: info@wellho.net • WEB: http://www.wellho.net • SKYPE: wellho

PAGE: http://www.wellho.net/mouth/4723_Con ... ython.html • PAGE BUILT: Sat Jun 11 12:16:26 2016 • BUILD SYSTEM: WomanWithCat