Neo4j: The football transfers graph
Date: 2015-07-16 06:40:26

Given we're still in http://www.bbc.co.uk/sport/0/football/33531715[pre season] http://www.bbc.co.uk/sport/0/football/33528451[transfer madness] as far as European football is concerned I thought it'd be interesting to put together a football transfers graph to see whether there are any interesting insights to be had.

It took me a while to find an appropriate source but I eventually came across http://www.transfermarkt.co.uk/premier-league/sommertransfers/wettbewerb/GB1/saison_id/2015[transfermarkt.co.uk] which contains transfers going back at least as far as the start of the Premier League in 1992.

I wrote a quick Python script to create a CSV file of all the transfers. This is what the file looks like:

[source,bash]
----

$ head -n 10 data/transfers.csv
player,from_team,from_team_id,to_team,to_team_id,fee,season
Martin Keown,Everton,29,Arsenal FC,11,"2,10 Mill. £",1992-1993
John Jensen,Bröndby IF,206,Arsenal FC,11,"1,12 Mill. £",1992-1993
Alan Miller,Birmingham,337,Arsenal FC,11,,1992-1993
Jim Will,Sheffield Utd.,350,Arsenal FC,11,,1992-1993
David Rocastle,Arsenal FC,11,Leeds,399,"1,68 Mill. £",1992-1993
Perry Groves,Arsenal FC,11,Southampton FC,180,595 Th. £,1992-1993
Ty Gooden,Arsenal FC,11,Wycombe Wand.,2805,?,1992-1993
Geraint Williams,Derby,22,Ipswich Town,677,525 Th. £,1992-1993
Jason Winters,Chelsea U21,9250,Ipswich Town,677,?,1992-1993
----

I'm going to create the following graph and then we'll write some queries which explore chains of transfers involving players and clubs.

image::{{<siteurl>}}/uploads/2015/07/2015-07-15_07-28-11.png[2015 07 15 07 28 11,599]

I wrote a few import scripts using Neo4j's http://neo4j.com/docs/stable/query-load-csv.html[LOAD CSV] command, having set up the appropriate indexes first:

[source,cypher]
----

create index on :Team(id);
create index on :Season(name);
create index on :Transfer(description);
create index on :Player(name);
----

[source,cypher]
----

// teams
load csv with headers from "file:///Users/markneedham/projects/football-transfers/data/teams.csv" as row
merge (team:Team {id: toint(row.team_id)})
on create set team.name = row.team;

// seasons
load csv with headers from "file:///Users/markneedham/projects/football-transfers/data/transfers.csv" as row
merge (season:Season {name: row.season})
ON CREATE SET season.starts =  toint(split(season.name, "-")[0]);

// players
load csv with headers from "file:///Users/markneedham/projects/football-transfers/data/transfers.csv" as row
merge (player:Player {name: row.player});

// transfers
load csv with headers from "file:///Users/markneedham/projects/football-transfers/data/transfers.csv" as row
match (from:Team {id: toint(row.from_team_id)})
match (to:Team {id: toint(row.to_team_id)})
match (season:Season {name: row.season})
match (player:Player {name: row.player})

merge (transfer:Transfer {description: row.player + " from " + from.name + " to " + to.name})
merge (transfer)-[:FROM_TEAM]->(from)
merge (transfer)-[:TO_TEAM]->(to)
merge (transfer)-[:IN_SEASON]->(season)
merge (transfer)-[:PLAYER]->(player);

// connect transfers
match (season)<-[:IN_SEASON]-(transfer:Transfer)-[:PLAYER]->(player)
WITH player, season, transfer
ORDER BY player.name, season.starts
WITH player, COLLECT({s: season, t: transfer}) AS transfers
UNWIND range(0, length(transfers)-2) AS idx
WITH player, transfers[idx] AS t1, transfers[idx +1] AS t2
WITH player, t1.t AS t1, t2.t AS t2
MERGE (t1)-[:NEXT]->(t2);
----

All the files and scripts are on https://gist.github.com/mneedham/2c0b28ebe2314cb5eab5[this gist] if you want to play around with the data. The only thing you'll need to change is the file path on each of the 'LOAD CSV' lines.

The 'connect transfers' query is a bit more complicated than the others - in that one we're first ordering the transfers in ascending order grouped by player and then http://www.markhneedham.com/blog/2015/06/04/neo4j-cypher-step-by-step-to-creating-a-linked-list-of-adjacent-nodes-using-unwind/[creating a linked list] of a player's transfers.

Now that we've got the data loaded let's find out which player was transferred the most:

[source,cypher]
----

match path = (:Transfer)-[:NEXT*0..]->(transfer:Transfer)
where NOT (transfer)-[:NEXT]->()
RETURN path
ORDER BY LENGTH(path) DESC
LIMIT 1
----

image::{{<siteurl>}}/uploads/2015/07/graph-22.png[Graph  22,599]

Which other players have moved teams frequently?

[source,cypher]
----

match path = (first:Transfer)-[:NEXT*0..]->(transfer:Transfer),
             (player)<-[:PLAYER]-(transfer)
where NOT ((transfer)-[:NEXT]->()) AND NOT ((first)<-[:NEXT]-())
RETURN player.name, LENGTH(path) AS numberOfTransfers
ORDER BY numberOfTransfers DESC
LIMIT 10

==> +--------------------------------------+
==> | player.name      | numberOfTransfers |
==> +--------------------------------------+
==> | "Craig Bellamy"  | 7                 |
==> | "David Unsworth" | 6                 |
==> | "Andrew Cole"    | 6                 |
==> | "Peter Crouch"   | 6                 |
==> | "Les Ferdinand"  | 5                 |
==> | "Kevin Phillips" | 5                 |
==> | "Mark Hughes"    | 5                 |
==> | "Tommy Wright"   | 4                 |
==> | "Carl Tiler"     | 4                 |
==> | "Don Hutchison"  | 4                 |
==> +--------------------------------------+
==> 10 rows
----

What are the most frequent combinations of clubs involved in transfers?

[source,cypher]
----

match (from)<-[:FROM_TEAM]-(t:Transfer)-[:TO_TEAM]->(to), (t)-[:PLAYER]->(p)
RETURN from.name, to.name, COUNT(*) AS times, COLLECT(p.name) AS players
ORDER BY times DESC
LIMIT 10

==> +------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
==> | from.name           | to.name               | times | players                                                                                                                                                                                                    |
==> +------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
==> | "West Ham United"   | "Queens Park Rangers" | 13    | ["Keith Rowland","Iain Dowie","Tim Breacker","Ludek Miklosko","Bertie Brayley","Terrell Forbes","Steve Lomas","Hogan Ephraim","Nigel Quashie","Danny Gabbidon","Kieron Dyer","Robert Green","Gary O'Neil"] |
==> | "Tottenham Hotspur" | "Portsmouth FC"       | 12    | ["Paul Walsh","Andy Turner","Rory Allen","Justin Edinburgh","Tim Sherwood","Teddy Sheringham","Noé Pamarot","Pedro Mendes","Sean Davis","Jermain Defoe","Younès Kaboul","Kevin-Prince Boateng"]            |
==> | "Liverpool FC"      | "West Ham United"     | 12    | ["Julian Dicks","David Burrows","Mike Marsh","Don Hutchison","Neil Ruddock","Titi Camara","Rob Jones","Rigobert Song","Craig Bellamy","Joe Cole","Andy Carroll","Stewart Downing"]                         |
==> | "Manchester United" | "Everton FC"          | 9     | ["Andrey Kanchelskis","John O'Kane","Jesper Blomqvist","Phil Neville","Tim Howard","Louis Saha","Darron Gibson","Sam Byrne","Tom Cleverley"]                                                               |
==> | "Newcastle United"  | "West Ham United"     | 9     | ["Paul Kitson","Shaka Hislop","Stuart Pearce","Wayne Quinn","Lee Bowyer","Kieron Dyer","Scott Parker","Nolberto Solano","Kevin Nolan"]                                                                     |
==> | "Blackburn Rovers"  | "Leicester City"      | 9     | ["Steve Agnew","Tim Flowers","Callum Davidson","John Curtis","Keith Gillespie","Craig Hignett","Nils-Eric Johansson","Bruno Berner","Paul Gallagher"]                                                      |
==> | "Chelsea FC"        | "Southampton FC"      | 8     | ["Ken Monkou","Kerry Dixon","Neil Shipperley","Mark Hughes","Paul Hughes","Graeme Le Saux","Jack Cork","Ryan Bertrand"]                                                                                    |
==> | "Birmingham City"   | "Coventry City"       | 8     | ["David Rennie","John Gayle","Liam Daish","Gary Breen","Stern John","Julian Gray","Lee Carsley","Gary McSheffrey"]                                                                                         |
==> | "Southampton FC"    | "Fulham FC"           | 8     | ["Micky Adams","Kevin Moore","Terry Hurlock","Maik Taylor","Alan Neilson","Luís Boa Morte","Antti Niemi","Chris Baird"]                                                                                    |
==> | "Portsmouth FC"     | "Stoke City"          | 8     | ["Kevin Harper","Lewis Buxton","Anthony Pulis","Vincent Péricard","Asmir Begovic","Marc Wilson","Elliot Wheeler","Alex Grant"]                                                                             |
==> +------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
==> 10 rows
----

Are there ever situations where players get transferred in both directions?

[source,cypher]
----

match (from)<-[:FROM_TEAM]-(t:Transfer)-[:TO_TEAM]->(to), (t)-[:PLAYER]->(player)
where id(from) < id(to)
WITH from, to, COUNT(*) AS times, COLLECT(player.name) AS players
match (to)<-[:FROM_TEAM]-(t:Transfer)-[:TO_TEAM]->(from), (t)-[:PLAYER]->(player)
RETURN from.name, to.name, times, COUNT(*) as otherWayTimes, players, COLLECT(player.name) AS otherWayPlayers
ORDER BY times + otherWayTimes DESC
LIMIT 10

==> +-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
==> | from.name           | to.name               | times | otherWayTimes | players                                                                                                                                                                                                    | otherWayPlayers                                                                                                                                                                    |
==> +-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
==> | "Tottenham Hotspur" | "Portsmouth FC"       | 12    | 5             | ["Paul Walsh","Andy Turner","Rory Allen","Justin Edinburgh","Tim Sherwood","Teddy Sheringham","Noé Pamarot","Pedro Mendes","Sean Davis","Jermain Defoe","Younès Kaboul","Kevin-Prince Boateng"]            | ["Jermain Defoe","Niko Kranjcar","Younès Kaboul","Peter Crouch","Darren Anderton"]                                                                                                 |
==> | "West Ham United"   | "Liverpool FC"        | 4     | 12            | ["Julian Dicks","Daniel Sjölund","Yossi Benayoun","Javier Mascherano"]                                                                                                                                     | ["Stewart Downing","Andy Carroll","Joe Cole","Craig Bellamy","Rigobert Song","Titi Camara","Rob Jones","Neil Ruddock","Don Hutchison","Julian Dicks","Mike Marsh","David Burrows"] |
==> | "West Ham United"   | "Queens Park Rangers" | 13    | 2             | ["Keith Rowland","Iain Dowie","Tim Breacker","Ludek Miklosko","Bertie Brayley","Terrell Forbes","Steve Lomas","Hogan Ephraim","Nigel Quashie","Danny Gabbidon","Kieron Dyer","Robert Green","Gary O'Neil"] | ["Andy Impey","Trevor Sinclair"]                                                                                                                                                   |
==> | "West Ham United"   | "Tottenham Hotspur"   | 5     | 8             | ["Jermain Defoe","Frédéric Kanouté","Michael Carrick","Jimmy Walker","Scott Parker"]                                                                                                                       | ["Sergiy Rebrov","Mauricio Taricco","Calum Davenport","Les Ferdinand","Matthew Etherington","Bobby Zamora","Ilie Dumitrescu","Mark Robson"]                                        |
==> | "West Ham United"   | "Portsmouth FC"       | 8     | 5             | ["Martin Allen","Adrian Whitbread","Marc Keller","Svetoslav Todorov","Hayden Foxe","Shaka Hislop","Sébastien Schemmel","Hayden Mullins"]                                                                   | ["Stephen Henderson","Teddy Sheringham","Shaka Hislop","Marc Keller","Lee Chapman"]                                                                                                |
==> | "Newcastle United"  | "West Ham United"     | 9     | 3             | ["Paul Kitson","Shaka Hislop","Stuart Pearce","Wayne Quinn","Lee Bowyer","Kieron Dyer","Scott Parker","Nolberto Solano","Kevin Nolan"]                                                                     | ["Demba Ba","Lee Bowyer","David Terrier"]                                                                                                                                          |
==> | "Birmingham City"   | "Coventry City"       | 8     | 4             | ["David Rennie","John Gayle","Liam Daish","Gary Breen","Stern John","Julian Gray","Lee Carsley","Gary McSheffrey"]                                                                                         | ["Scott Dann","David Burrows","Peter Ndlovu","David Smith"]                                                                                                                        |
==> | "Manchester City"   | "Portsmouth FC"       | 8     | 4             | ["Paul Walsh","Carl Griffiths","Fitzroy Simpson","Eyal Berkovic","David James","Andrew Cole","Sylvain Distin","Tal Ben Haim"]                                                                              | ["Benjani","Gerry Creaney","Kit Symons","Paul Walsh"]                                                                                                                              |
==> | "Blackburn Rovers"  | "Southampton FC"      | 5     | 6             | ["David Speedie","Stuart Ripley","James Beattie","Kevin Davies","Zak Jones"]                                                                                                                               | ["Zak Jones","Egil Östenstad","Kevin Davies","Alan Shearer","Jeff Kenna","Tim Flowers"]                                                                                            |
==> | "AFC Bournemouth"   | "West Ham United"     | 3     | 8             | ["Keith Rowland","Paul Mitchell","Scott Mean"]                                                                                                                                                             | ["Steve Jones","Matt Holland","Mohammed Berthé","Scott Mean","Paul Mitchell","Jamie Victory","Mark Watson","Stephen Purches"]                                                      |
==> +-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
----

Any players who go back to the same club they were at previously?

[source,cypher]
----

match (player:Player)<-[:PLAYER]-(t1:Transfer)-[:FROM_TEAM]->(from)<-[:TO_TEAM]-(t2:Transfer)-[:FROM_TEAM]->(to),
      (t2)-[:PLAYER]->(player), (t1)-[:TO_TEAM]->(to)
WHERE ID(to) < ID(from)
WITH player, COLLECT([ from.name, " ⥄ ", to.name]) AS teams
RETURN player.name,
       REDUCE(acc = [], item in teams | acc  + REDUCE(acc2 = "", i in item | acc2 + i)) AS thereAndBack
ORDER BY LENGTH(thereAndBack) DESC
LIMIT 10

==> +-------------------------------------------------------------------------------------+
==> | player.name       | thereAndBack                                                    |
==> +-------------------------------------------------------------------------------------+
==> | "Mark Stein"      | ["Stoke City ⥄ Chelsea FC","Ipswich Town ⥄ Chelsea FC"]         |
==> | "Peter Beagrie"   | ["Bradford City ⥄ Everton FC","Bradford City ⥄ Wigan Athletic"] |
==> | "Richard Dryden"  | ["Southampton FC ⥄ Stoke City","Southampton FC ⥄ Swindon Town"] |
==> | "Robbie Elliott"  | ["Bolton Wanderers ⥄ Newcastle United"]                         |
==> | "Elliot Grandin"  | ["Blackpool FC ⥄ Crystal Palace"]                               |
==> | "Robert Fleck"    | ["Chelsea FC ⥄ Norwich City"]                                   |
==> | "Paul Walsh"      | ["Portsmouth FC ⥄ Manchester City"]                             |
==> | "Rick Holden"     | ["Manchester City ⥄ Oldham Athletic"]                           |
==> | "Gary McAllister" | ["Liverpool FC ⥄ Coventry City"]                                |
==> | "Lee Bowyer"      | ["West Ham United ⥄ Newcastle United"]                          |
==> +-------------------------------------------------------------------------------------+
----

That's all I've got for now - if you can think of any other interesting avenues to explore let me know and I'll take a look.