Fix: Get_player_stats_by_week() Returns Empty Stats

by Alex Johnson 52 views

If you've encountered an issue where the get_player_stats_by_week() method is returning empty stats, you're not alone. This article dives deep into this problem, exploring the reasons behind it and offering practical workarounds. We'll cover everything from the initial bug report to a detailed investigation, including API response analysis and a proposed solution. Let's unravel this mystery together.

The Initial Problem: Empty Player Stats

The core issue arises when using the get_player_stats_by_week() method. Despite successfully querying the Yahoo Fantasy API, the method returns a Player object with an empty player_stats object. This means that even when you're looking for stats for players who actively participated in a specific week, you're met with a blank slate. This can be incredibly frustrating, especially when you're trying to analyze player performance or build a fantasy team strategy.

Environment Details

To give you a clear picture, here are the environmental details where this issue was observed:

  • yfpy version: 1.2.7
  • Python version: 3.12
  • Sport: NBA (game_code: "nba", game_id: 466)
  • Query method: get_player_stats_by_week(player_key, chosen_week, limit_to_league_stats=True/False)

Expected vs. Actual Behavior

Expected Behavior: Ideally, when you call get_player_stats_by_week() for a player who played in a given week, the method should return a Player object filled with the player's weekly statistics. This includes points, rebounds, assists, and other relevant stats.

Actual Behavior: Instead, the method returns a Player object containing the player's basic identity information (name, team, etc.), but the player_stats attribute is an empty PlayerStats({}) object. This object has no stats, rendering the query ineffective. The breakdown looks like this:

player_stats.stats = []  # Empty list
player_stats.coverage_type = ''  # Empty string
player_stats.week = None  # No week information

Reproducing the Issue

To illustrate the problem, here’s a Python code snippet that reproduces the issue:

from yfpy.query import YahooFantasySportsQuery

query = YahooFantasySportsQuery(
    game_code="nba",
    game_id=466,
    league_id=LEAGUE_ID,
    yahoo_consumer_key="YOUR_KEY",
    yahoo_consumer_secret="YOUR_SECRET",
    env_file_location="path/to/.env"
)

# Test with a known player who played in week 4
week_stats = query.get_player_stats_by_week(
    player_key="466.p.6679",  # Brandon Williams
    chosen_week=4,
    limit_to_league_stats=True
)

print(f"Player: {week_stats.name.full}")
print(f"Has player_stats: {hasattr(week_stats, 'player_stats')}")
print(f"player_stats: {week_stats.player_stats}")
print(f"Stats count: {len(week_stats.player_stats.stats)}")

When you run this code, you’ll likely see the following output:

Player: Brandon Williams
Has player_stats: True
player_stats: PlayerStats({})
Stats count: 0

This output confirms that while the player_stats attribute exists, it’s empty, and no statistics are being returned.

Diving Deeper: Investigation and Analysis

To understand why this is happening, a thorough investigation was conducted, focusing on API response analysis and examining the raw JSON structure returned by the Yahoo Fantasy API.

API Response Analysis

The initial step was to verify whether the Yahoo Fantasy API was indeed returning data. The tests confirmed that the API does return data successfully. The response size, approximately 1400 bytes, indicates that player information is being transmitted. However, yfpy fails to extract the stats from the response.

Two query modes were tested:

  1. With limit_to_league_stats=True (default):
    • URL: https://fantasysports.yahooapis.com/fantasy/v2/league/466.l.12558/players;player_keys=466.p.6679/stats;type=week;week=4
    • Response: 200 OK (1397 bytes)
    • Result: Empty stats
  2. With limit_to_league_stats=False:
    • URL: https://fantasysports.yahooapis.com/fantasy/v2/players;player_keys=466.p.6679/stats;type=week;week=4
    • Response: 200 OK
    • Result: Empty stats

Both modes returned an HTTP 200 OK status, indicating a successful request, but the stats remained elusive.

Examining the Raw API Response Structure

To pinpoint the issue, the raw JSON response from the Yahoo API was scrutinized. The player data is nested in a complex array structure:

{
  "fantasy_content": {
    "league": [
      { /* league metadata */ },
      {
        "players": {
          "0": {
            "player": [
              [
                { "player_key": "466.p.6679" },
                { "player_id": "6679" },
                { "name": { ... } },
                /* ... player attributes ... */
                /* NOTE: No player_stats object found in this structure */
              ]
            ]
          }
        }
      }
    ]
  }
}

Interestingly, the stats are not included in the response when querying individual players by week. This is despite the URL including the parameters ;type=week;week=4. This revelation is crucial in understanding the root cause.

Uncovering the Root Cause: A Yahoo API Limitation

The investigation revealed a significant limitation: the Yahoo Fantasy Sports API does not return weekly player stats when querying individual players directly through the following endpoints:

  • /league/{league_key}/players;player_keys={key}/stats;type=week;week={week}
  • /players;player_keys={key}/stats;type=week;week={week}

This is not a parsing bug within yfpy, but rather a constraint imposed by the Yahoo Fantasy API itself. It's a critical distinction that changes the approach to resolving the issue.

The Workaround: Leveraging the Team Roster Endpoint

While the direct player query fails, there's a silver lining: weekly player stats can be retrieved using the team roster endpoint. This workaround involves querying team rosters and then extracting the player stats from the roster data. Here’s how it can be done:

# Instead of querying player directly, query team rosters
standings = query.get_league_standings()

for team in standings.teams:
    roster_stats = query.get_team_roster_player_stats_by_week(
        team.team_id,
        chosen_week=4
    )

    for player in roster_stats:
        if player.player_id == "6679":  # Brandon Williams
            print(f"Player: {player.name.full}")
            print(f"Stats count: {len(player.player_stats.stats)}")
            for stat in player.player_stats.stats:
                print(f"  Stat ID {stat.stat_id}: {stat.value}")

Executing this code will yield the desired weekly stats:

Player: Brandon Williams
Stats count: 11
  Stat ID 9004003: 0.0  # (FGM/FGA - see composite stats bug)
  Stat ID 5: 0.409     # FG%
  Stat ID 9007006: 0.0  # (FTM/FTA)
  Stat ID 8: 0.875     # FT%
  Stat ID 10: 1.0      # 3PTM
  Stat ID 12: 58.0     # PTS
  Stat ID 15: 16.0     # REB
  Stat ID 16: 23.0     # AST
  Stat ID 17: 7.0      # STL
  Stat ID 18: 0.0      # BLK
  Stat ID 19: 9.0      # TO

This workaround provides a reliable way to access weekly player stats, albeit through a slightly different route.

Questions for Maintainers and Community Discussion

This discovery raises several important questions for the maintainers of yfpy and the wider community:

  1. Is this a known Yahoo API limitation? Have other sports/endpoints exhibited similar behavior? Understanding the scope of this limitation is crucial for comprehensive API handling.
  2. Should the method documentation be updated to explicitly state that weekly player stats are only reliably available through team roster queries? Clear documentation prevents confusion and guides users to the correct methods.
  3. Should get_player_stats_by_week() raise a warning or exception when it detects empty stats, rather than silently returning an empty PlayerStats object? This proactive approach can alert users to the issue and prompt them to use the workaround.

Proposed Documentation Update

To address the documentation concern, here’s a proposed update for the get_player_stats_by_week() method’s docstring:

def get_player_stats_by_week(self, player_key: str, chosen_week: Union[int, str] = "current",
                             limit_to_league_stats: bool = True) -> Player:
    """Retrieve stats of specific player by player_key and by week for chosen league.

    **Note**: The Yahoo Fantasy API may not return weekly stats when querying
    individual players directly. If player_stats is empty, use
    get_team_roster_player_stats_by_week() instead to retrieve weekly player
    statistics through team rosters.

    Args:
        player_key (str): The player key of chosen player
        chosen_week (int): Selected week for which to retrieve data
        limit_to_league_stats (bool): Limit stats to the selected league

    Returns:
        Player: Player instance (may have empty player_stats for weekly queries)
    """

This updated documentation clearly highlights the limitation and directs users to the appropriate workaround.

Additional Context and Related Issues

This issue was initially discovered while implementing weekly stat tracking for fantasy basketball matchup summaries. The team roster method (get_team_roster_player_stats_by_week) functions correctly and returns complete weekly stats, reinforcing the workaround's viability. Season stats, accessed via get_player_stats_for_season(), work correctly for individual player queries, indicating that the issue is specific to weekly stats queries.

This behavior may stem from how Yahoo structures their API responses differently for collection queries versus individual resource queries. Understanding these nuances is crucial for effective API usage.

This issue is related to PR #69, which addressed a weekly stats aggregation fix, and also touches on a separate composite stats parsing bug, highlighting the complexity of fantasy sports API interactions.

Conclusion: Navigating the Yahoo Fantasy API Limitations

In conclusion, the empty stats returned by get_player_stats_by_week() are not due to a bug in yfpy, but rather a limitation of the Yahoo Fantasy Sports API. While this can be frustrating, understanding the root cause allows us to implement effective workarounds. By using the get_team_roster_player_stats_by_week() method, you can still access the weekly player stats you need.

Remember to consult the API documentation and community discussions to stay informed about such limitations and best practices. By sharing our experiences and insights, we can collectively enhance our understanding and utilization of these powerful tools. For more information on Yahoo Fantasy API and its limitations, visit the Yahoo Fantasy Sports API Documentation. This external resource can provide additional context and guidance for your fantasy sports data endeavors.