'IF' Syntax For Alternative Conditions

[rshepard]

All my python books and references I find on the web have simplistic
examples of the IF conditional. A few also provide examples of multiple
conditions that are ANDed; e.g.,
if cond1:
if cond2:
do_something.

However, I cannot find, nor create by trial-and-error, the syntax for
alternative conditions that are ORed; e.g.,

if cond1 OR if cond2:
do_something.

I've tried using the C syntax for OR (||) but python complained. I'm sure
there's a way to do this rather than using if cond1: elif cond2: both with
the same code to execute.

Please pass me a pointer so I can learn how to correctly write this.

Rich

 

[Leif K-Brooks]

However, I cannot find, nor create by trial-and-error, the syntax for
alternative conditions that are ORed; e.g.,

if cond1 OR if cond2:
do_something.

if cond1 or cond2:
do_something()

 

[Paul Rubin]

if cond1:
if cond2:
do_something.

You can write:
if cond1 and cond2:
do_something

if cond1 OR if cond2:
do_something.

if cond1 or cond2:
do_something

I've tried using the C syntax for OR (||) but python complained. I'm sure
there's a way to do this rather than using if cond1: elif cond2: both with
the same code to execute.

Python uses the "and" and "or" keywords for && and ||.

 

[Gabriel Genellina]

However, I cannot find, nor create by trial-and-error, the syntax for
alternative conditions that are ORed; e.g.,

if cond1 OR if cond2:
do_something.

Please pass me a pointer so I can learn how to correctly write this.

See the Python tutorial:
http://docs.python.org/tut/node7.html#SECTION007700000000000000000
Note that most (if not all) Python keywords are lowercase.

 

[Duncan Booth]

Note that most (if not all) Python keywords are lowercase.

All keywords are lower case.

and del from not while
as elif global or with
assert else if pass yield
break except import print
class exec in raise
continue finally is return
def for lambda try

'None' is not entirely lowercase, and you cannot assign to it, but
technically it isn't a keyword.

 

[James Stroud]

All my python books and references I find on the web have simplistic
examples of the IF conditional. A few also provide examples of multiple
conditions that are ANDed; e.g.,
if cond1:
if cond2:
do_something.

However, I cannot find, nor create by trial-and-error, the syntax for
alternative conditions that are ORed; e.g.,

if cond1 OR if cond2:
do_something.

I've tried using the C syntax for OR (||) but python complained. I'm sure
there's a way to do this rather than using if cond1: elif cond2: both with
the same code to execute.

Please pass me a pointer so I can learn how to correctly write this.

Rich

For lots of conditions:

import operator
reduce(operator.or_, list_of_conditions)

e.g.:

py> import operator
py> list_of_conditions = [
.... 'big' < 'small',
.... 'all' > 'half',
.... 'five' > 'one',
.... 'six' < 'seven'
.... ]
py> list_of_conditions
[True, False, False, False]
py> reduce(operator.or_, list_of_conditions)
True

James

 

[rshepard]

You can write:
if cond1 and cond2:
do_something


if cond1 or cond2:
do_something


Python uses the "and" and "or" keywords for && and ||.

Allow me to thank all of you who responded with this one article. For
whatever reason, it did not occur to me to use the words 'and' and 'or.'
And, I did not see this in the tutorial or introduction ... which is my
fault.

So, I do thank all of you.

Rich