python

Check for falsy values - None, False, blank in Python

To check for falsy values like None, False, blank value in Python you can use methods explained in this post.

val1 = ''
if val1:
    print("Not a falsy value")
else:
    print("Falsy value")
# -> Falsy value


val2 = 'devsheet'
if val2:
    print("Not a falsy value")
# -> Not a falsy value

We are checking falsy values here we are just placing Python variable after if statement and if the value is not falsy the block code inside if statement will be executed.

value = None

if value:
    print('Value is not falsy')
else:
    print('Value is falsy')

Output

Value is falsy

Check falsy values using bool() function

We can also use the bool() function to check for falsy values in Python. This function will return False for Falsy values and returns True for truth value. We can understand them using below code examples.

bool(['a', 'b', 'c'])
# -> True

bool([])
# -> False

bool(30)
# -> True

bool(0)
# -> False

bool(0.0)
# False

bool(-10)
# True

bool(True)
# -> True

bool(False)
# -> False

bool({'name': 'Rick', 'value': '30'})
# -> True

bool({})
# -> False

bool(None)
# -> False

bool(range(0))
# False

bool(set())
# False

if bool([]):
  print('List is empty')

So we can check if a list is empty using the bool() function. The bool() function will return False if the given list is empty.

Check falsy value using in keyword

value = 10

if value not in ['', None]:
    print('Value is not blank or none')

We are checking here if the value is not blank or None.

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