How to deal with null values using Python format

Question

I'm looking for a way to essentially strip out the extra period if a value is null or None. If myvar doesn't exist, it should print abc.xyz

myvar="def"
print "abc.{0}.xyz".format(myvar)
abc.def.xyz

myvar=""
print "abc.{0}.xyz".format(myvar)
abc..xyz

Answer 1

If a character is present in the original string it will be included regardless after calling format for it. What needs to be done is to modify the input such that it will include whatever extra character when the intended value is present. Consider the following (encapsulated in a function as a demo):

def demo(value):
    print("abc.{0}xyz".format(value + '.' if value else ''))

Example usage:

>>> demo('def')
abc.def.xyz
>>> demo('')
abc.xyz