#ACTIVIDAD DE R

#install.packages("dslabs")
library(dslabs)

data("movielens")

summary(movielens)
##     movieId          title                year     
##  Min.   :     1   Length:100004      Min.   :1902  
##  1st Qu.:  1028   Class :character   1st Qu.:1987  
##  Median :  2406   Mode  :character   Median :1995  
##  Mean   : 12549                      Mean   :1992  
##  3rd Qu.:  5418                      3rd Qu.:2001  
##  Max.   :163949                      Max.   :2016  
##                                      NA's   :7     
##                   genres          userId        rating        timestamp        
##  Drama               : 7757   Min.   :  1   Min.   :0.500   Min.   :7.897e+08  
##  Comedy              : 6748   1st Qu.:182   1st Qu.:3.000   1st Qu.:9.658e+08  
##  Comedy|Romance      : 3973   Median :367   Median :4.000   Median :1.110e+09  
##  Drama|Romance       : 3462   Mean   :347   Mean   :3.544   Mean   :1.130e+09  
##  Comedy|Drama        : 3272   3rd Qu.:520   3rd Qu.:4.000   3rd Qu.:1.296e+09  
##  Comedy|Drama|Romance: 3204   Max.   :671   Max.   :5.000   Max.   :1.477e+09  
##  (Other)             :71588
#Vector sin los Na
vector_yearsClean <- movielens$year[!is.na(movielens$year)]
#print(vector_yearsClean)
#Vector aƱos Na
vector_yearsNa <- movielens$year[is.na(movielens$year)]
#print(vector_yearsNa)

#Df con valores en year sin Na
df_yearsClean <- movielens[!is.na(movielens$year), ]
#Df con valores en year Na
df_yearsNa <- movielens[is.na(movielens$year), ]

#DF con las peores peliculas
df_peoresPeliculas <- df_yearsClean[df_yearsClean$rating < 3.5,]
summary(df_peoresPeliculas)
##     movieId          title                year     
##  Min.   :     1   Length:37895       Min.   :1902  
##  1st Qu.:   838   Class :character   1st Qu.:1990  
##  Median :  2405   Mode  :character   Median :1995  
##  Mean   : 11839                      Mean   :1993  
##  3rd Qu.:  4974                      3rd Qu.:2000  
##  Max.   :162672                      Max.   :2016  
##                                                    
##                   genres          userId          rating     
##  Comedy              : 3292   Min.   :  1.0   Min.   :0.500  
##  Drama               : 2399   1st Qu.:187.0   1st Qu.:2.000  
##  Comedy|Romance      : 1848   Median :375.0   Median :3.000  
##  Drama|Romance       : 1176   Mean   :347.2   Mean   :2.435  
##  Comedy|Drama        : 1122   3rd Qu.:514.0   3rd Qu.:3.000  
##  Comedy|Drama|Romance: 1101   Max.   :671.0   Max.   :3.000  
##  (Other)             :26957                                  
##    timestamp        
##  Min.   :7.897e+08  
##  1st Qu.:9.600e+08  
##  Median :1.077e+09  
##  Mean   :1.113e+09  
##  3rd Qu.:1.272e+09  
##  Max.   :1.477e+09  
##