# Day 23: Python Basic Statistics

One of the interesting exercises for Python so far, I want to share my source code for the question I extracted from the online learning website. The datasets for heights and positions are pre-randomized from the website.

• Convert `heights` and `positions`, which are regular lists, to numpy arrays. Call them `np_heights` and `np_positions`.
• Extract all the heights of the goalkeepers. You can use a little trick here: use `np_positions == 'GK'` as an index for `np_heights`. Assign the result to `gk_heights`.
• Extract all the heights of all the other players. This time use `np_positions != 'GK'` as an index for `np_heights`. Assign the result to `other_heights`.
• Print out the median height of the goalkeepers using `np.median()`. Replace `None` with the correct code.
• Do the same for the other players. Print out their median height. Replace `None` with the correct code.
```# Import numpy
import numpy as np

# Convert positions and heights to numpy arrays: np_positions, np_heights
np_heights = np.array(heights)
np_positions = np.array(positions)

# Heights of the goalkeepers: gk_heights
gk_heights = np_heights[np_positions == 'GK']

# Heights of the other players: other_heights
other_heights = np_heights[np_positions != 'GK']

# Print out the median height of goalkeepers. Replace 'None'
print("Median height of goalkeepers: " + str(np.median(gk_heights)))

# Print out the median height of other players. Replace 'None'
print("Median height of other players: " + str(np.median(other_heights)))
```

The output of the above source code execution is,

Median height of goalkeepers: 188.0
Median height of other players: 181.0