pandas how to check all values in column are in another code example

Example 1: finding the rows in a dataframe where column contains any of these values python

import pandas as pd

data = {'Month': ['January','February','March','April','May','June','July','August','September','October','November','December'],
        'Days in Month': [31,28,31,30,31,30,31,31,30,31,30,31]
        }

df = pd.DataFrame(data, columns = ['Month', 'Days in Month'])

contain_values = df[df['Month'].str.contains('Ju')]
print (contain_values)

Example 2: pandas check if any of the values in one column exist in another

df["exists"] = df.drop("target", 1).isin(df["target"]).any(1)
print(df)

    target  A       B       C       exists
0   cat     bridge  cat     brush   True
1   brush   dog     cat     shoe    False
2   bridge  cat     shoe    bridge  True