Intro

Hattrick is a once-very-popular online football game that is quite addictive. As recently the results of my team have not been amazing I started playing a bit with its API. I will write about how I build a library to:

1. Query the hattrick API
2. Save data about the first 4 leagues in Italy.

The API

The Hattrick API is well documented [here][chpp] and the only difficult thing is to be able to set up a OAuth authentication procedure, which was solved by using this nice library. Once the authentication part was overcome by copying some snippets of code over and over until they worked I started to realise I needed a bit more than one call to get all the information I needed. As I kept defining function after function and my file kept getting bigger I decided eventually to put everything in one big file and call it pyhattrick.

At this point getiing the team data is as easy as doing:

import pyhattrick as pht 
#get the series id 
seriesid = pht.get_series_id_from_name("Serie A")
#get the teams info
teams = pht.get_teams_from_series_id(seriesid)
#and do the same for II, III, IV series

All team infos are then saved in a pandas dataframe and collected so they look kinda like this:

The next step involves some data manipulation in order to aggregate the data at the regional level.

Data aggregation

The team’s name is not really interesting, we just want to get the number of teams that play in a certain region, per serie.

In order to create the groups we just do:

groups = teams.groupby(by=["region","serie"])

We then create the region list dinamically, so we don’t need to write it by hand:

for g in groups:
    if g[0][0] not in region_list:
        region_list.append(g[0][0])

Last, we loop on the regions and fill 4 lists with the number of teams playing in each region, per serie. For example, for serie A we do:

for region in region_list:
    for g in groups:
        if g[0][0]==region and g[0][1]=="Serie A":
            a_list.append(len(g[1]))
            break
    else:
        a_list.append(0)

The last step is to create a dataframe from the created lists (region, serie A teams, II serie team and so on):

data = pd.DataFrame({'region': region_list, 'a': a_list, 'ii': ii_list, 'iii': iii_list, 'iv': iv_list})

The result is the following dataframe:

We save the dataframe into a csv file.

Data Visualisation

Once we have the csv file the only thing left is to link it to a map and show the data as as points or regions in the map.

For example we can show a map of Italy and color the regions with different shades, with darker shades corresponding to regions with more teams.

Hovering over the regions you get an overview of how the teams in the selected region are distributed by serie.