How to check whether a variable is empty?

Question

class dheepak():
    age = 23
    name = "dheepak sasi"

ankit = getattr(dheepak, "hostname", ' ')
if ankit == None:
    print "Shanaya"
else:
    print "byee"
mani = dheepak.age

print ankit

if hostname doesnot exist than it should print Shanaya if hostname present than print byee. And hostname value is coming from another program sometimes it comes sometimes not

Or http://stackoverflow.com/questions/9926446/how-to-check-whether-a-strvariable-is-empty-or-not — Chris_Rands, May 08 '17 at 13:55

chepner · Answer 1 · 2017-05-08T14:15:38.360

4

You are supplying a space as the value for ankit if there is no such attribute, but checking for None. Be consistent:

ankit = getattr(dheepak, "hostname", None)
if ankit is None:
   ...

or

ankit = getattr(dheepak, "hostname", ' ')
if ankit == ' ':
   ...

Better yet, don't try to define a sentinel value at all; just catch the exception raised by getattr when the attribute doesn't exist.

try:
    ankit = getattr(dheepak, "hostname")
except AttributeError:
    print "Shanaya"
else:
    print "byee"

edited May 08 '17 at 14:15

answered May 08 '17 at 13:56

chepner

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Since they don't need the attribute value, `hasattr` might be more appropriate. – Moses Koledoye May 08 '17 at 13:59
I haven't done more than dabble with Python 3, so I still avoid `hasattr`. https://hynek.me/articles/hasattr/ – chepner May 08 '17 at 14:07

score 0 · Answer 2 · answered May 08 '17 at 13:55

0

How about this:

class dheepak():
    age = 23
    name = "dheepak sasi"

ankit = getattr(dheepak, "hostname", '')
if not ankit:
    print "Shanaya"
else:
    print "byee"
mani = dheepak.age

print ankit

answered May 08 '17 at 13:55

zipa

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How to check whether a variable is empty?

2 Answers2