Learning immediately: https://edu.csdn.net/course/play/27352/363919?utm_source=blogtoedu
1, handle missing values
nan non-sensitive function
np.nansum ()
2, missing values found
isnull
notnull
Each function returns a Boolean type of mask data
3, excluding missing values
dropna: Excluding missing values. Commonly used two parameters:
axis: control remove rows or columns
thresh: less than the number of rows or columns of data culling
fillna: missing values populated with another value
4, fill in missing values
Filled function is fillna, as common parameters:
axis: axis
method: fill mode
ffill.forward-fill, back fill front
bfill.backward-fill, forwardly from the filling
