# MovieLens Dataset

The MovieLens Dataset was collected by GroupLens Research. The data set contains some user information, movie information, and many movie ratings from [1-5]. The data sets have many version depending on the size of set. We use MovieLens 1M Dataset as a demo dataset, which contains 1 million ratings from 6000 users on 4000 movies. Released 2/2003.

## Dataset Features

In ml-1m Dataset, there are many features in these dataset. The data files (which have ”.dat” extension) in ml-1m Dataset is basically CSV file that delimiter is ”::”. The description in README we quote here.

### RATINGS FILE DESCRIPTION(ratings.dat)

All ratings are contained in the file “ratings.dat” and are in the following format:

UserID::MovieID::Rating::Timestamp

- UserIDs range between 1 and 6040
- MovieIDs range between 1 and 3952
- Ratings are made on a 5-star scale (whole-star ratings only)
- Timestamp is represented in seconds since the epoch as returned by time(2)
- Each user has at least 20 ratings

### USERS FILE DESCRIPTION(users.dat)

User information is in the file “users.dat” and is in the following format:

UserID::Gender::Age::Occupation::Zip-code

All demographic information is provided voluntarily by the users and is not checked for accuracy. Only users who have provided some demographic information are included in this data set.

- Gender is denoted by a “M” for male and “F” for female
- Age is chosen from the following ranges:
  - 1: “Under 18”
  - 18: “18-24”
  - 25: “25-34”
  - 35: “35-44”
  - 45: “45-49”
  - 50: “50-55”
  - 56: “56+”
- Occupation is chosen from the following choices:
  - 0: “other” or not specified
  - 1: “academic/educator”
  - 2: “artist”
  - 3: “clerical/admin”
  - 4: “college/grad student”
  - 5: “customer service”
  - 6: “doctor/health care”
  - 7: “executive/managerial”
  - 8: “farmer”
  - 9: “homemaker”
  - 10: “K-12 student”
  - 11: “lawyer”
  - 12: “programmer”
  - 13: “retired”
  - 14: “sales/marketing”
  - 15: “scientist”
  - 16: “self-employed”
  - 17: “technician/engineer”
  - 18: “tradesman/craftsman”
  - 19: “unemployed”
  - 20: “writer”

### MOVIES FILE DESCRIPTION(movies.dat)

Movie information is in the file “movies.dat” and is in the following format:

MovieID::Title::Genres

- Titles are identical to titles provided by the IMDB (including year of release)
- Genres are pipe-separated and are selected from the following genres:
  - Action
  - Adventure
  - Animation
  - Children’s
  - Comedy
  - Crime
  - Documentary
  - Drama
  - Fantasy
  - Film-Noir
  - Horror
  - Musical
  - Mystery
  - Romance
  - Sci-Fi
  - Thriller
  - War
  - Western
- Some MovieIDs do not correspond to a movie due to accidental duplicate entries and/or test entries
- Movies are mostly entered by hand, so errors and inconsistencies may exist