## Grouping Rows by Month in Pandas

Grouping rows by month in Pandas is a common task for data analysts and scientists. It helps to analyze and summarize data based on monthly trends. With Pandas, you can easily group rows based on a certain period, such as months. Let’s dive in!

### 1) Grouping Rows by Month in Pandas

To group rows by month in Pandas, you need to use the `.groupby()`

method along with the `.dt.month`

attribute. Let’s see the syntax to group rows by month in Pandas:

`DataFrame.groupby(DataFrame['column_name'].dt.month)`

This syntax uses the `.groupby()`

method and `.dt.month`

attribute to group rows according to months.

The `DataFrame['column_name']`

is the column you want to group by, such as a date or time column.

For example, let’s say we have a sales dataset that contains a date column and we want to group the data by month.

Here’s an example code:

```
sales = pd.read_csv('sales.csv') # reading sales dataset
sales['Date'] = pd.to_datetime(sales['Date']) # converting Date column to datetime format
sales.groupby(sales['Date'].dt.month).sum()
```

This code will group the sales dataset by month and calculate the sum of sales for each month. The result will be a pandas DataFrame that contains the sum of sales for each month.

### 2) Using dt.month() Function in Pandas

Another way to group rows by month in Pandas is to use the `.dt.month()`

function. This function returns the month of each element in a datetime column.

Let’s see the syntax to use the `dt.month()`

function in Pandas:

`DataFrame['datetime_column'].dt.month`

This syntax uses the `.dt.month()`

function to extract the month from a datetime column. The `DataFrame['datetime_column']`

is the datetime column you want to extract the month from.

For example, let’s say we have the same sales dataset as before and we want to group the data by month using the `dt.month()`

function. Here’s the example code:

```
sales = pd.read_csv('sales.csv') # reading sales dataset
sales['Date'] = pd.to_datetime(sales['Date']) # converting Date column to datetime format
sales['Month'] = sales['Date'].dt.month # creating a new column that contains the month
sales.groupby('Month').sum()
```

This code will create a new column ‘Month’ that contains the month from the ‘Date’ column and then group the sales dataset by the month column.

The result will be the sum of sales for each month.

## Conclusion

In conclusion, grouping rows by month in Pandas is a quick and easy way to analyze and summarize data on a monthly basis. Using the `.groupby()`

method and `.dt.month`

attribute or the `.dt.month()`

function can help you to achieve this task effectively.

Hopefully, this article has provided you with a good foundation for grouping your data based on monthly trends. Happy coding!

## 3) Calculating Values Grouped by Month in Pandas

Calculating values grouped by month is an essential task in data analysis. Several mathematical operations like sum, mean, maximum, minimum, etc., can be performed on the data grouped by month.

In pandas, we can easily calculate these values using the `.groupby()`

method with the appropriate mathematical function like `.sum()`

, `.mean()`

, `.max()`

, etc. Syntax to calculate the sum or max of values grouped by month in pandas:

`DataFrame.groupby(DataFrame['column_name'].dt.month)['value_column'].sum()`

To calculate the sum or max of values grouped by month in pandas, we need to use the `.groupby()`

method.

In the syntax, `DataFrame['column_name']`

is the column name containing dates, and `'value_column'`

is the column containing the values to be calculated.

### Example:

Here is an example of how to calculate the sum of sales grouped by month in pandas:

```
sales = pd.read_csv('sales.csv') # reading sales dataset
sales['Date'] = pd.to_datetime(sales['Date']) # converting Date column to datetime format
monthly_sales = sales.groupby(sales['Date'].dt.month)['Sales'].sum().reset_index() # calculating sum of sales by month and resetting index
print(monthly_sales)
```

In this example, we have imported the sales dataset and converted the date column to a datetime format. The `.groupby()`

method with the `.sum()`

function is used to calculate the sum of values (Sales column) grouped by month (using the `.dt.month`

attribute).

The `.reset_index()`

method is used to reset the index. Finally, we print the result using the `print()`

function.

The output of the above code will be a DataFrame that contains the sum of sales for each month.

## Conclusion

In this article, we covered important topics related to grouping data by month in pandas.

We first looked at how to group rows by month in pandas using the `.groupby()`

method with the `.dt.month`

attribute. Then, we saw another way to group rows by month in pandas using the `.dt.month()`

function.

Next, we discussed how to calculate values grouped by month in pandas using appropriate mathematical functions like `.sum()`

, `.mean()`

, `.max()`

, etc., with examples to illustrate the syntax.

Now that you have a good understanding of grouping data by month in pandas, you can use these methods to analyze and summarize your own datasets effectively.

Happy coding!

In this article, we discussed the importance of grouping data by month in pandas, which is a common task in data analysis. We covered two methods for grouping rows by month using the `.groupby()`

method with the `.dt.month`

attribute and the `.dt.month()`

function.

We also saw how to calculate values like the sum or max grouped by month using appropriate mathematical functions. Grouping data by month helps to analyze and summarize data based on monthly trends.

The takeaways from this article are that pandas provides efficient ways to group data by month, and it is essential to analyze data based on monthly trends to gain insights.