There's a differece between "the same", "equal" and "identical". I can have two identical 5p coins, but they're not the same coin. And I can have two coins which are not identical, but are equal in value. And when you're checking for equality in a program, you should know which you're looking at. Take a look at this in Python:

  >>> a = [10]
  >>> b = [10]
  >>> c = a
  >>> a == b
  True
  >>> a is b
  False
  >>> a is c
  True
  >>>

a and b are different lists, but they contain identical information. c is another name for the list which is also called a.

The == operator tells you whether two variables (or expressions) contain equal values, whether or not they're the same actual object.

The is operator tells you whether two variable names point to the same object.

A list (as used above) is a mutable object - something that can be changed within itself. Integers, floats, strings and tuples are immutable - in other words if you want to change something, you need to create a new replacement object. And in Python, identical immutable objects are stored only once for efficiency - so you'll find a different set of results from using is ... if two immutable objects are identical, they'll be the same object. Thus:

  >>> a = 10
  >>> b = 10
  >>> c = a
  >>> a == b
  True
  >>> a is b
  True
  >>> a is c
  True
  >>>
(written 2013-05-17, updated 2013-05-18)

 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)
  [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)
  [4723] Conditional operators in Python - (2016-11-05)

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