check if dataframe column values is same code example

Example 1: 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

Example 2: python pandas check if two columns are equal

df = pd.DataFrame([[2, 2], [3, 6]], columns = ["col1", "col2"])