Is It Possible To Assign A Default Value When Unpacking?

I have the following: >>> myString = 'has spaces' >>> first, second = myString.split() >>> myString = 'doesNotHaveSpaces' >>> first, second = my

Solution 1:

May I suggest you to consider using a different method, i.e. partition instead of split:

>>>myString = "has spaces">>>left, separator, right = myString.partition(' ')>>>left
'has'
>>>myString = "doesNotHaveSpaces">>>left, separator, right = myString.partition(' ')>>>left
'doesNotHaveSpaces'

If you are on python3, you have this option available:

>>>myString = "doesNotHaveSpaces">>>first, *rest = myString.split()>>>first
'doesNotHaveSpaces'
>>>rest
[]

Solution 2:

A general solution would be to chain your iterable with a repeat of None values and then use an islice of the result:

from itertools import chain, islice, repeat

none_repat = repeat(None)
example_iter = iter(range(1)) #orrange(2) orrange(0)

first, second= islice(chain(example_iter, none_repeat), 2)

this would fill in missing values with None, if you need this kind of functionality a lot you can put it into a function like this:

deffill_iter(it, size, fill_value=None):
    return islice(chain(it, repeat(fill_value)), size)

Although the most common use is by far for strings which is why str.partition exists.

Solution 3:

Here's one general solution to unpack tuple and use default value if tuple is shorter than expected:

unpacker = lambda x,y=1,z=2:(x,y,z)

packed =(8,5)
a,b,c= unpacker(*packed)
print(a,b,c)# 8 5 2

packed =(8,)
a,b,c= unpacker(*packed)
print(a,b,c)# 8 1 2

Play with this code

Solution 4:

You could try this:

NUM2UNPACK=2   
parts = myString.split()    
first, second= parts+[None]*(NUM2UNPACK-(len(parts)))