How to test NoneType in python? - Stack Overflow Since None is the sole singleton object of NoneType in Python, we can use is operator to check if a variable has None in it or not Quoting from is docs , The operators is and is not test for object identity: x is y is true if and only if x and y are the same object
Determining a variables type is NoneType in python I would like to check if a variable is of the NoneType type For other types we can do stuff like: type([])==list But for NoneType this simple way is not possible That is, we cannot say type(
Python identify if variable is NoneType - Stack Overflow Python is complaining that you want to obtain an index from a None object (like None[0]) and this fails You should check that first: while lines_hp is not None and lines_hp[0] is not None: print lines_hp[0] is not None #some operation to change lines_hp[0]
python - What is a NoneType object? - Stack Overflow In Python NoneType is the type of the None object ; There is only one such object Therefore, "a None object" and "the None object" and "None" are three equivalent ways of saying the same thing
nonetype - not None test in Python - Stack Overflow As for why the val != None is not recommended: If val can be either None or a more complex thing, like a numpy array, it's not entirely clear whether this intends to be an element-wise comparison (e g: arr>0 will produce a list of indices at which elements of arr are positive), so if you expect val to be either an array or None, then arr is None is the safest way to test this
python - Where is the NoneType located? - Stack Overflow Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: type 'NoneType' is not an acceptable base type * As of Python 3 10, you could use types NoneType , to be consistent with the other singleton types being added to the types module
python - Check for None in pandas dataframe - Stack Overflow You could use applymap with a lambda to check if an element is None as follows, (constructed a different example, as in your original one, None is coerced to np nan because the data type is float, you will need an object type column to hold None as is, or as commented by @Evert, None and NaN are indistinguishable in numeric type columns):
python - TypeError: NoneType object is not iterable - Stack Overflow None has no __iter__ method defined, so Python's virtual machine tells you what it sees: that NoneType has no __iter__ method This is why Python's duck-typing ideology is considered bad The programmer does something completely reasonable with a variable and at runtime it gets contaminated by None, the python virtual machine attempts to