Explicit comparison to singleton can be unreadable
Bad:
if number == None: print(“This works, but is not the preferred PEP 8 pattern”)
if number ! = None : print(“This works, but is not the preferred PEP 8 pattern”)
if otherNumber == false
print(“yooo !”)
if otherNumber != false
print(“yooo !”)
if T_flag == True :
print ( “This works, but is not the preferred PEP 8 pattern” )
if F_flag ! = True :
print ( “This works, but is not the preferred PEP 8 pattern” )
good:
if number is None : print ( “This works, but is not the preferred PEP 8 pattern” )
if not otherNumber
print ( “yooo !” )
# or better :
if not otherNumber and otherNumber is not None
print ( “yooo !” )
if not otherNumber
print ( “yooo !” )
if T_ flag :
print ( “PEP 8 Style Guide prefers this pattern” )
if T_ flag is True :
print ( “PEP 8 Style Guide prefers this pattern” )
if not F_ flag :
print ( “PEP 8 Style Guide prefers this pattern” )
Why you should care
None is the pattern if Cond is None . This is only a guideline. It can be ignored if needed. But the purpose of the PEP 8 style guidelines is to improve the readability of code.
Python evaluates certain values as false when in a boolean context. A quick “rule of thumb” is that all “empty” values are considered false so 0, None, [], {}, '' all evaluate as false in a boolean context. So comparing to “false” may be confusing.
Moreover, conditions using Python booleans are easier to read and less error-prone. In most cases, they’re also faster
Per the PEP 8 Style Guide, the preferred ways to compare something to True are the patterns if cond is True: or if cond: . This is only a guideline. It can be ignored if needed. But the purpose of the PEP 8 Style Guide is to improve the readability of code.
Business Impacts
It is recommended to avoid these in order to ensure the code is more readable and cost effective.
CAST recommendations
References
http://docs.quantifiedcode.com/python-code-patterns/readability/comparison_to_none.html
https://google.github.io/styleguide/pyguide.html#Conditional_Expressions
http://docs.quantifiedcode.com/python-code-patterns/readability/comparison_to_true.html
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