Python: Fix - TypeError: NoneType object is not iterable

Code:

def print_names(names):
  for name in names:
      print(names)

names = None
print_names(names)

Error trace:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-26-481a76948b73> in <cell line: 6>()
      4 
      5 names = None
----> 6 print_names(names)

<ipython-input-26-481a76948b73> in print_names(names)
      1 def print_names(names):
----> 2   for name in names:
      3       print(names)
      4 
      5 names = None

TypeError: 'NoneType' object is not iterable

Reason for the TypeError

As you can see, the names variable is declared as type None, you cannot iterate over None types in Python.

Fix:

It is better to first check if the type is not None before iterating.

def print_names(names):
  if(names is None):
    print("Names list is empty...")
  else:
    for name in names:
      print(names)

names = None
print_names(names)

Output: Names list is empty...

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