rede_bigrams_discurso_impeachment.R

library(dplyr)
library(rvest)
library(stringr)

url_tabela_discursos <- "http://www.camara.leg.br/internet/sitaqweb/resultadoPesquisaDiscursos.asp?txOrador=&txPartido=&txUF=&dtInicio=17%2F04%2F2016&dtFim=17%2F04%2F2016&txTexto=&txSumario=&basePesq=plenario&CampoOrdenacao=dtSessao&PageSize=5000&TipoOrdenacao=DESC&btnPesq=Pesquisar"

url_discursos <- url_tabela_discursos %>%
  read_html() %>%
  html_nodes(xpath = "//table[@class ='table table-bordered variasColunas']//td/a") %>%
  html_attr(name = "href")

url_discursos <- str_c("http://www.camara.leg.br/internet/sitaqweb/", url_discursos)
url_discursos <- str_replace_all(url_discursos, " ", "")
url_discursos <- str_replace_all(url_discursos, "\r", "")
url_discursos <- str_replace_all(url_discursos, "\n", "")
url_discursos <- str_subset(url_discursos, "http://www.camara.leg.br/internet/sitaqweb/TextoHTML.asp?")

discursos <- c()
for (url_discurso in url_discursos) {
  
  discurso <- url_discurso %>%
    read_html() %>%
    html_nodes(xpath = "//div[@id  = 'content']//p") %>%
    html_text()
  
  discursos <- c(discursos, discurso)
  
  Sys.sleep(0.5)
}

library(tidytext)
library(ggplot2)
library(tidyr)
library(tm)

discursos_df <- data_frame(id_discurso = 1:length(discursos), 
                           text = discursos)

discurso_bigrams <- discursos_df %>%
  unnest_tokens(bigram, text, token = "ngrams", n = 2)

discurso_bigrams %>%
  count(bigram, sort = TRUE)

bigrams_separated <- discurso_bigrams %>%
  separate(bigram, c("word1", "word2"), sep = " ")

stopwords_pt <- c(stopwords("pt"), "é")
stopwords_pt_df <- data.frame(word = stopwords_pt)

bigrams_filtered <- bigrams_separated %>%
  anti_join(stopwords_pt_df, by = c("word1" = "word")) %>%
  anti_join(stopwords_pt_df, by = c("word2" = "word"))

bigram_counts <- bigrams_filtered %>% 
  count(word1, word2, sort = TRUE)

library(igraph)
library(ggraph)

bigram_graph <- bigram_counts %>%
  filter(n > 20) %>%
  graph_from_data_frame()

ggraph(bigram_graph, layout = "fr") +
  geom_edge_link() +
  geom_node_point() +
  geom_node_text(aes(label = name), vjust = 1, hjust = 1)