Shortened if in if-else construct
The if-else construction can be used in a shortened form if we need to check whether a variable is true. In a broad sense, this means whether the variable is equal to the Boolean value True. In the short form, after if, it is enough to simply write the variable name without any conditions for comparison:
tst = True
if tst:
print('+++') # this will work
else:
print('---')
You can also use the shorthand if when the variable has values equal to Boolean ones.
Values that evaluate to False
None- integer
0 - floating point number
0.0 - empty string
'' - empty list
[] - empty tuple
() - empty dictionary
{} - empty set
set()
All other values are set to True.
Let's check if the variable tst is equal to the value True:
tst = 5
if tst:
print('+++') # this will work
else:
print('---')
Tell me what will be the result of executing this code:
tst = []
if tst:
print('+++')
else:
print('---')
Tell me what will be the result of executing this code:
tst = None
if tst:
print('+++')
else:
print('---')
Tell me what will be the result of executing this code:
tst = -1
if tst:
print('+++')
else:
print('---')
Tell me what will be the result of executing this code:
tst = False
if tst:
print('+++')
else:
print('---')
Tell me what will be the result of executing this code:
tst = True
if tst:
print('+++')
else:
print('---')
Tell me what will be the result of executing this code:
tst = 'False'
if tst:
print('+++')
else:
print('---')
Tell me what will be the result of executing this code:
tst = '0'
if tst:
print('+++')
else:
print('---')
Tell me what will be the result of executing this code:
tst = ()
if tst:
print('+++')
else:
print('---')
Tell me what will be the result of executing this code:
tst = [0]
if tst:
print('+++')
else:
print('---')
Tell me what will be the result of executing this code:
tst = 1 - 1
if tst:
print('+++')
else:
print('---')
Tell me what will be the result of executing this code:
tst = {}
if tst:
print('+++')
else:
print('---')
Tell me what will be the result of executing this code:
tst = set()
if tst:
print('+++')
else:
print('---')
Tell me what will be the result of executing this code:
tst = ''
if tst:
print('+++')
else:
print('---')
