# Finding Quantiles of a Column in a DataFrame

We can find many different quantiles for sets of numbers using the `.quantile()`

function of a DataFrame. One specific quantiles, the 50% quantile, is almost universally known since it is the **median**!

If the numbers in a column are organized in ascending order, the **median** is the value that rests directly in the middle of the data, with **50%** on the left side (and the right side, but we focus specifically on the left side when we think of quantiles). We can also find the 25% quantile, which is the value with 25% of the data to the left, and the 75% quantile, which is the value with 75% of the data to the left.

## The Movie Dataset

Let's use a small DataFrame with information about movies to see this function in action!

```
import pandas as pd
# Creates a DataFrame of "movie", "release date", "domestic gross", "worldwide gross", "personal rating", and "international box office" columns
df = pd.DataFrame([
{"movie": "The Truman Show", "release date": "1996-06-05", "domestic box office": 125618201, "worldwide box office": 264118201, "personal rating": 10, "international box office": 138500000},
{"movie": "Rogue One: A Star Wars Story", "release date": "2016-12-16", "domestic box office": 532177324, "worldwide box office": 1055135598, "personal rating": 9, "international box office": 522958274},
{"movie": "Iron Man", "release date": "2008-05-02", "domestic box office": 318604126, "worldwide box office": 585171547, "personal rating": 7, "international box office": 266567421},
{"movie": "Blade Runner", "release date": "1982-06-25", "domestic box office": 32656328, "worldwide box office": 39535837, "personal rating": 8, "international box office": 6879509},
{"movie": "Breakfast at Tiffany's", "release date": "1961-10-05", "domestic box office": 9551904, "worldwide box office": 9794721, "personal rating": 7, "international box office": 242817}
])
df
```

movie | release date | domestic box office | worldwide box office | personal rating | international box office | |
---|---|---|---|---|---|---|

0 | The Truman Show | 1996-06-05 | 125618201 | 264118201 | 10 | 138500000 |

1 | Rogue One: A Star Wars Story | 2016-12-16 | 532177324 | 1055135598 | 9 | 522958274 |

2 | Iron Man | 2008-05-02 | 318604126 | 585171547 | 7 | 266567421 |

3 | Blade Runner | 1982-06-25 | 32656328 | 39535837 | 8 | 6879509 |

4 | Breakfast at Tiffany's | 1961-10-05 | 9551904 | 9794721 | 7 | 242817 |

## Choosing the Quantile

The usefulness of `.quantile()`

function lies with its parameter. By default, the function calculates the 50% quantile (the median). This is kind of redundant, though, because we already have a `.median()`

function that returns the same result.

We can change which quantile the function calculates by inputting our own decimal parameter. For example, to calculate the 25^{th} percentile, type 0.25 in the parenthesis.

However, we are not limited to 0.25, 0.5, and 0.75. We can input any number between 0 and 1 to calculate more complicated quantiles.

Additional explanations, videos, and example problems covering quantiles is part of the DISCOVERY course content found here:

## Finding Multiple Quantiles

We can also input a list of decimals to get every quantile we want at once. The result will be in list format.