Scraping Fantasy projections from fantasypros.com

fantasy_pros_scrape.R

library(tidyverse)
library(glue)
library(rvest)

# Function to scrape the top avg cap salary by player ----
scrape_projections <- function(position, week) {
        
        if (position == "qb") {
                naming <- c("", "PASS", "PASS", 'PASS', "PASS", "PASS", "RUSH", "RUSH", "RUSH", "", "")
        } else if (position == "rb") {
                naming <-  c("", "RUSH", "RUSH", "RUSH", "REC", "REC","REC", "", "")
        } else if (position == "wr") {

                naming <- c("", "REC", "REC","REC", "RUSH", "RUSH", "RUSH", "", "")
        } else {
                naming <- c("", "REC", "REC","REC", "", "")
        }
        
        # Be nice
        Sys.sleep(1)
        
        message(glue::glue("Scraping projected stats for {position} wk: {week}!"))
        
        url <- glue::glue("https://www.fantasypros.com/nfl/projections/{position}.php?week=draft")
        
        url %>%
                read_html() %>% 
                html_table() %>% 
                .[[1]] %>% 
                filter(X1 != "") %>%
                set_names(nm = .[1,]) %>%
                .[2:length(.$Player),] %>% 
                set_names(., paste({naming}, names(.), sep = "_")) %>% 
                rename("Player" = "_Player", "FL" = "_FL", "FPTS" = "_FPTS") %>% 
                mutate(position = toupper({position}),
                       week = week) %>% 
                mutate(team = str_sub(Player, -3),
                       team = str_extract(team, "[[:upper:]]+"),
                       Player = str_remove(Player, team),
                       Player = str_trim(Player)) %>% 
                select(Player, team, position, week, everything()) %>%
                rename_all(tolower)
        }

# define inputs

position <- c("qb", "rb", "wr", "te")
week <- c("draft", as.character(1:16))

# crossing for all combos of inputs
crossing(position, week)

# scrape the data
df_output <- crossing(position = position, week = week) %>% 
        pmap_dfr(scrape_projections) %>%
        mutate_at(vars(pass_yds, rush_yds, rec_yds), str_remove, ",") %>% 
        mutate_at(vars(pass_att:rec_tds), as.numeric) %>%
        mutate_at(vars(team:position), as.factor) %>% 
        as_tibble()

# Just yearly total projections
df_total <- filter(df_output, week == "draft") %>% 
        select(-week)

# Just weekly projections
df_weekly <- filter(df_output, week != "draft") %>% 
        mutate(week = as.integer(week)) %>% 
        arrange(week)

Ok - one more freebie @samhoppen:

# scrape the data
df_output <- crossing(position = position, week = week) %>% 
        pmap_dfr(scrape_projections) %>%
        mutate_at(vars(pass_yds, rush_yds, rec_yds), str_remove, ",") %>% 
        mutate_at(vars(pass_att:rec_tds), as.numeric) %>%
        mutate_at(vars(team:position), as.factor) %>% 
        as_tibble()

# Just yearly total projections
df_total <- filter(df_output, week == "draft") %>% 
        select(-week)

model_all <- df_total %>% 
        rowwise() %>% 
        mutate(tds = sum(rush_tds, pass_tds, rec_tds, na.rm = TRUE),
               opp = sum(pass_att, rush_att, rec_rec, na.rm = TRUE)) %>% 
        ungroup() %>% 
        group_by(position) %>% 
        top_n(32, fpts) %>% 
        nest() %>% 
        rowwise() %>% 
        summarize(model = lm(fpts ~ opp, data) %>% glance()) %>% 
        unpack(model) %>% 
        ungroup() %>%
        select(position, r.squared) %>% 
        mutate(r.squared = round(r.squared, 3),
               label = paste(position, r.squared, sep = " R^2: "))

model_all

plot_all <- df_total %>% 
        rowwise() %>% 
        mutate(tds = sum(rush_tds, pass_tds, rec_tds, na.rm = TRUE),
               opp = sum(pass_att, rush_att, rec_rec, na.rm = TRUE)) %>% 
        ungroup() %>% 
        group_by(position) %>% 
        top_n(32, fpts) %>% 
        ungroup() %>% 
        left_join(model_all, by = c("position")) %>% 
        ggplot(aes(x = opp, y = fpts)) +
        geom_point(aes(size = tds)) +
        geom_smooth(method = "lm") +
        facet_wrap(~label, scales = "free")



plot_all

This is great, Tom! You rock! I tried running this but kept getting an error that "Column model must be length 1 (a summary value), not 11" - I'm not as familiar with the lm() function so wondering if there's a quick fix. Last question, I promise!

I bet you're not using the dev version of dplyr! 🤦 That's my bad!

The summarize workflow + rowwise() is a replacement for purrr::map() in this example for dplyr 1.0.

That's not on CRAN yet, so I'd check out the following:

model_all <- df_total %>% 
  rowwise() %>% 
  mutate(tds = sum(rush_tds, pass_tds, rec_tds, na.rm = TRUE),
         opp = sum(pass_att, rush_att, rec_rec, na.rm = TRUE)) %>% 
  group_by(position) %>% 
  top_n(32, fpts) %>% 
  nest() %>% 
  ungroup() %>% 
  mutate(model = map(data, ~ lm(fpts ~ opp, data = .x)), # rather than rowwise + summarize
            glanced = map(model, broom::glance)) %>%     # we do mutate + map()
  unnest(glanced) %>% 
  select(position, r.squared) %>% 
  mutate(r.squared = round(r.squared, 3),
         label = paste(position, r.squared, sep = " R^2: "))

model_all