In today’s quick tutorial we’ll using Python and the Pandas library to calculate the mean of one or more columns in a Pandas DataFrame.

Let’s get started by prepping our test DataFrame. As usual, we’ll use the auto-generated candidates data.

Here we go:

```
import pandas as pd
data = pd.read_csv('survey.csv')
print(data)
```

Here’s the result (note that you can copy and paste the following data and use the pd.read_clipboard() method to populate your own dataframe and follow along.

month | salary | num_candidates | |
---|---|---|---|

1 | April | 118.0 | 83.0 |

2 | February | 127.0 | 80.0 |

3 | May | 122.0 | 75.0 |

4 | July | 146.0 | 82.0 |

5 | September | 122.0 | 79.0 |

6 | February | 130.0 | 90.0 |

7 | July | 118.0 | 73.0 |

8 | November | 116.0 | 77.0 |

9 | February | 114.0 | 88.0 |

10 | October | 147.0 | 78.0 |

### Find the mean / average of one column

To find the average of one column (Series), we simply type:

`data['salary'].mean()`

The result will be 126.

### Calculate mean of multiple columns

In our case, we can simply invoke the mean() method on the DataFrame itself.

`data['salary'].mean()`

The result will be:

```
salary 126.0
num_candidates 80.5
dtype: float64
```

Chances are that your DataFrame will be wider, and contains several columns. In that case, we’ll first subset our DataFrame by the relevant columns and then calculate the mean.

```
cols = ['salary', 'num_candidates']
data[cols].mean()
```

The result will be similar.

### Moving on: Creating a DataFrame or list from your columns mean values

You can easily turn your mean values into a new DataFrame or to a list:

```
data_mean = pd.DataFrame(data.mean(), columns=['mean_values'])
#create list of mean values
mean_lst = data.mean().to_list
```

### Plot column average in Pandas

As the Pandas library contains basic methods for plotting, making a simple chart to visualize multiple column averages is a breeze:

`data.mean().plot(kind='bar');`

Here’s the chart:

### Calculate the mean of you Series with df.describe()

We can use the DataFrame method pd.describe to quickly look into the key statistical calculations of our DataFrame numeric columns – including the mean.

`data.describe().round()`

And the result:

### Calculate the median of a DataFrame

For completeness, here’s a simple snippet to calculate the median of multiple DataFrame columns:

```
data.median()
```

This will render the following results, which represent the median observation of each columns of the dataset.

salary 122.0 num_candidates 79.5 dtype: float64