pandas || df.dropna() missing value deletion

The df.dropna() function is used to delete missing data in the dataframe data, that is, delete NaN data.

Official function description:

DataFrame.dropna(axis=0, how='any', thresh=None, subset=None, inplace=False)
	Remove missing values.

	See the User Guide for more on which values are considered missing, 
	and how to work with missing data.

Returns
	DataFrame
	DataFrame with NA entries dropped from it.

Parameter Description:

Parameters	illustrate
axis	0 is the row and 1 is the column, default 0, the data deletes the dimension
how	{'any', 'all'}, default 'any', any: delete rows with nan; all: delete rows with all nan
thresh	int, keep at least int non-nan rows
subset	list, missing value handling in specific columns
inplace	bool, whether to modify the source file

test:

>>>df = pd.DataFrame({
    
    "name": ['Alfred', 'Batman', 'Catwoman'],
                   "toy": [np.nan, 'Batmobile', 'Bullwhip'],
                   "born": [pd.NaT, pd.Timestamp("1940-04-25"),
                            pd.NaT]})

>>>df
       name        toy       born
0    Alfred        NaN        NaT
1    Batman  Batmobile 1940-04-25
2  Catwoman   Bullwhip        NaT

Delete rows with at least one element missing:

>>>df.dropna()
     name        toy       born
1  Batman  Batmobile 1940-04-25

Drop columns that are missing at least one element:

>>>df.dropna(axis=1)
       name
0    Alfred
1    Batman
2  Catwoman

Delete all rows with missing elements:

>>>df.dropna(how='all')
       name        toy       born
0    Alfred        NaN        NaT
1    Batman  Batmobile 1940-04-25
2  Catwoman   Bullwhip        NaT

Only keep rows with at least 2 non-NA values:

>>>df.dropna(thresh=2)
       name        toy       born
1    Batman  Batmobile 1940-04-25
2  Catwoman   Bullwhip        NaT

Find missing values ​​from a specific column:

>>>df.dropna(subset=['name', 'born'])
       name        toy       born
1    Batman  Batmobile 1940-04-25

Modify the original data:

>>>df.dropna(inplace=True)
>>>df
     name        toy       born
1  Batman  Batmobile 1940-04-25

that's all.