if var == False

In python you can write an if statement as follows

var = True
if var:
print 'I\'m here'

is there any way to do the opposite without the ==, eg

var = False
if !var:
print 'learnt stuff'

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var = False
if not var: print 'learnt stuff'

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Python uses not instead of ! for negation.

Try

if not var:
print "learnt stuff"

instead

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最佳答案

Use not

var = False
if not var:
print 'learnt stuff'

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I think what you are looking for is the 'not' operator?

if not var

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Since Python evaluates also the data type NoneType as False during the check, a more precise answer is:

var = False
if var is False:
print('learnt stuff')

This prevents potentially unwanted behaviour such as:

var = []  # or None
if not var:
print('learnt stuff') # is printed what may or may not be wanted

But if you want to check all cases where var will be evaluated to False, then doing it by using logical not keyword is the right thing to do.