checking for the existence of an attribute

[Bob Roberts]

I'm sure there must be a better way to do this:

try:
if item.page:
DoSomething()
except AttributError:
pass

Is there a simple way to check if item has "page" as one of its attributes?

 

[Peter Otten]

I'm sure there must be a better way to do this:

try:
if item.page:
DoSomething()
except AttributError:
pass

Is there a simple way to check if item has "page" as one of its
attributes?

try:
item.page
except AttributeError:
pass
else:
doSomething()


or

if hasattr(item, "page"):
doSomething()

Peter

 

[Dave Kuhlman]

I'm sure there must be a better way to do this:

try:
if item.page:
DoSomething()
except AttributError:
pass

Is there a simple way to check if item has "page" as one of its
attributes?

Look at built-in function `getattr`.

http://www.python.org/doc/current/lib/built-in-funcs.html

Dave

 

[Terry Reedy]

I'm sure there must be a better way to do this:

try:
if item.page:
DoSomething()
except AttributError:
pass

This checks both the item.page exists and that it has a True value.
Is that exactly the check you want? Catching attribute errors with
try..except a standard Python idiom.

Is there a simple way to check if item has "page" as one of its

attributes?

enter 'help(hasattr)' at prompt or check lib ref 'builtin functions'.
If item is often missing a page, (>10% of tries), then explicit test
might be better.

Terry J. Reedy