How do I use the merge function in pandas?

How do I use the merge function in pandas?

The merge function in pandas is used to combine two DataFrames based on a common column or index. You can specify how to merge them using parameters like 'on', 'how', and 'left_index'.

Can you give me an example of merging two DataFrames?

Sure! Here's a simple example:

import pandas as pd

df1 = pd.DataFrame({'key': ['A', 'B', 'C'], 'value1': [1, 2, 3]})
df2 = pd.DataFrame({'key': ['B', 'C', 'D'], 'value2': [4, 5, 6]})

merged_df = pd.merge(df1, df2, on='key', how='inner')
print(merged_df)

This will merge df1 and df2 on the 'key' column using an inner join.

What are the different types of joins I can use?

You can use several types of joins: 'inner', 'outer', 'left', and 'right'. Each type determines how to handle rows that don't match.

Is it possible to merge on multiple columns?

Yes, you can merge on multiple columns by passing a list to the 'on' parameter, like this:

merged_df = pd.merge(df1, df2, on=['key1', 'key2'], how='inner')