Fetching MLB Player Height Data

This function parses the height string (in ft and in) and converts to float

# convert height string from ft and in to ft
parse_height <- function(height_str) {
  # split str into ft and in components
  height_parts <- strsplit(height_str, "' ")[[1]]
  feet <- as.numeric(height_parts[1])
  inches <- as.numeric(gsub('"', '', height_parts[2]))
  
  # convert height to ft units
  height_in_feet <- feet + inches / 12
  return(height_in_feet)
}

This chunks the ID list to ensure no single API call has more than 500 IDs

chunk_list <- function(lst, chunk_size) {
  split(lst, ceiling(seq_along(lst) / chunk_size))
}

The API call below takes player_id integer vector as input and builds a data frame with id, height and weight

# fetch player heights given their IDs
get_player_heights <- function(player_ids) {
  all_data <- list()

  # split player IDs into chunks
  chunks <- chunk_list(player_ids, 500)

  for (chunk in chunks) {
    # convert the chunk of player IDs to a comma-separated string
    player_id_str <- paste(chunk, collapse = ",")
    url <- paste0('https://statsapi.mlb.com/api/v1/people?personIds=', player_id_str, '&fields=people,id,height,weight')

    # get the response from the API
    response <- GET(url)

    # check if the request was successful
    if (http_status(response)$category != "Success") {
      stop("HTTP request failed")
    }

    # parse the JSON response
    json_data <- content(response, as = "parsed", simplifyVector = TRUE)$people

    # convert to a data frame and apply height parsing
    data <- as.data.frame(json_data)
    data$height <- sapply(data$height, parse_height)
    all_data <- append(all_data, list(data))
    
    # sleep to avoid overloading server
    Sys.sleep(0.5)
  }

  # combine chunks into a single data frame
  result_df <- bind_rows(all_data)
  return(result_df)
}

Example Query

We can now fetch the heights of a couple of players

# example player IDs
player_ids <- c(694973, 573186)

# fetch the data
player_df <- get_player_heights(player_ids)

head(player_df)

##       id   height weight
## 1 694973 6.500000    235
## 2 573186 5.583333    180