pythonpandasdataframedata-analysisexploratory-data-analysis

count the matching elements between two dataframes

df1.location = 'United Arab Emirates',
 'Bahrain',
 'Luxembourg',
 'Malta',
 'Denmark',
 'Israel',
 'Iceland',
 'Russia',
 'United States',
 'Australia'

df2.location ='Qatar',
 'Bahrain',
 'Panama',
 'Chile',
 'San Marino',
 'Aruba',
 'Kuwait',
 'Peru',
 'Brazil',
 'United States'
​ ```
And i have to find the number of matching elements between two pandas dataframes.
Solution

  • Assuming df1 and df2 to be:

    df1 = pd.DataFrame({'location': ['United Arab Emirates', 'Bahrain', 'Luxembourg', 'Malta', 'Denmark', 'Israel', 'Iceland', 'Russia', 'United States', 'Australia']})
df2 = pd.DataFrame({'location': ['Qatar', 'Bahrain', 'Panama', 'Chile', 'San Marino', 'Aruba', 'Kuwait', 'Peru', 'Brazil', 'United States']})

    If you want the number of elements matching on the same row/index:

    df1['location'].eq(df2['location']).sum()

    output: 1 (only row index 1 matches)

    If you want the number of matching unique elements, independently of their position:

    len(set(df1['location'])&set(df2['location']))

    output: 2 ('Bahrain' and 'United States' are common)