How to do aggregation/ summarization

Summarization after grouping

library(tidyverse)
iris %>% 
  group_by(Species) %>% 
  summarize(Support = mean(Sepal.Length)) %>%    # average
  arrange(-Support)                         # sort
## # A tibble: 3 × 2
##   Species    Support
##   <fct>        <dbl>
## 1 virginica     6.59
## 2 versicolor    5.94
## 3 setosa        5.01
iris %>% 
  group_by(Species) %>% 
summarize(mean_s = mean(Sepal.Width), 
            meas_p = mean(Petal.Length), 
            diff = mean(Sepal.Width-Petal.Length)) %>% 
  arrange(-diff) 
## # A tibble: 3 × 4
##   Species    mean_s meas_p  diff
##   <fct>       <dbl>  <dbl> <dbl>
## 1 setosa       3.43   1.46  1.97
## 2 versicolor   2.77   4.26 -1.49
## 3 virginica    2.97   5.55 -2.58
iris %>% 
  group_by(Species) %>% 
summarize(n = n(), 
            meas_p = mean(Petal.Length), 
            sd = sd(Petal.Length))  
## # A tibble: 3 × 4
##   Species        n meas_p    sd
##   <fct>      <int>  <dbl> <dbl>
## 1 setosa        50   1.46 0.174
## 2 versicolor    50   4.26 0.470
## 3 virginica     50   5.55 0.552

Summarization with upgroup

iris %>% 
  ungroup( ) %>% 
summarize(n = n(), 
            meas_p = mean(Petal.Length), 
            sd = sd(Petal.Length))  
##     n meas_p       sd
## 1 150  3.758 1.765298

Mutate new variables after grouping

iris %>% 
  group_by(Species) %>% 
mutate(n = n(), 
            meas_p = mean(Petal.Length), 
            sd = sd(Petal.Length))  
## # A tibble: 150 × 8
## # Groups:   Species [3]
##    Sepal.Length Sepal.Width Petal.Length Petal.Width Species     n meas_p    sd
##           <dbl>       <dbl>        <dbl>       <dbl> <fct>   <int>  <dbl> <dbl>
##  1          5.1         3.5          1.4         0.2 setosa     50   1.46 0.174
##  2          4.9         3            1.4         0.2 setosa     50   1.46 0.174
##  3          4.7         3.2          1.3         0.2 setosa     50   1.46 0.174
##  4          4.6         3.1          1.5         0.2 setosa     50   1.46 0.174
##  5          5           3.6          1.4         0.2 setosa     50   1.46 0.174
##  6          5.4         3.9          1.7         0.4 setosa     50   1.46 0.174
##  7          4.6         3.4          1.4         0.3 setosa     50   1.46 0.174
##  8          5           3.4          1.5         0.2 setosa     50   1.46 0.174
##  9          4.4         2.9          1.4         0.2 setosa     50   1.46 0.174
## 10          4.9         3.1          1.5         0.1 setosa     50   1.46 0.174
## # … with 140 more rows
iris %>% 
  group_by(Species) %>% 
mutate(n = n(), 
            meas_p = mean(Petal.Length, na.rm = T), 
            sd = sd(Petal.Length))  %>% 
  summarize (n_mean = paste ("sample size:",mean(n)), 
            meas_p = mean(Petal.Length), 
            sd = sd(Petal.Length))
## # A tibble: 3 × 4
##   Species    n_mean          meas_p    sd
##   <fct>      <chr>            <dbl> <dbl>
## 1 setosa     sample size: 50   1.46 0.174
## 2 versicolor sample size: 50   4.26 0.470
## 3 virginica  sample size: 50   5.55 0.552

Recode and generate new variables, then value label

irisifelse <- iris %>% 
mutate(Species2 = ifelse(Species == "setosa", NA, Species))
# relabel values
irisifelse$Species2 <- factor(irisifelse$Species2,labels = c( "versi","virg"))
irisifelse
##     Sepal.Length Sepal.Width Petal.Length Petal.Width    Species Species2
## 1            5.1         3.5          1.4         0.2     setosa     <NA>
## 2            4.9         3.0          1.4         0.2     setosa     <NA>
## 3            4.7         3.2          1.3         0.2     setosa     <NA>
## 4            4.6         3.1          1.5         0.2     setosa     <NA>
## 5            5.0         3.6          1.4         0.2     setosa     <NA>
## 6            5.4         3.9          1.7         0.4     setosa     <NA>
## 7            4.6         3.4          1.4         0.3     setosa     <NA>
## 8            5.0         3.4          1.5         0.2     setosa     <NA>
## 9            4.4         2.9          1.4         0.2     setosa     <NA>
## 10           4.9         3.1          1.5         0.1     setosa     <NA>
## 11           5.4         3.7          1.5         0.2     setosa     <NA>
## 12           4.8         3.4          1.6         0.2     setosa     <NA>
## 13           4.8         3.0          1.4         0.1     setosa     <NA>
## 14           4.3         3.0          1.1         0.1     setosa     <NA>
## 15           5.8         4.0          1.2         0.2     setosa     <NA>
## 16           5.7         4.4          1.5         0.4     setosa     <NA>
## 17           5.4         3.9          1.3         0.4     setosa     <NA>
## 18           5.1         3.5          1.4         0.3     setosa     <NA>
## 19           5.7         3.8          1.7         0.3     setosa     <NA>
## 20           5.1         3.8          1.5         0.3     setosa     <NA>
## 21           5.4         3.4          1.7         0.2     setosa     <NA>
## 22           5.1         3.7          1.5         0.4     setosa     <NA>
## 23           4.6         3.6          1.0         0.2     setosa     <NA>
## 24           5.1         3.3          1.7         0.5     setosa     <NA>
## 25           4.8         3.4          1.9         0.2     setosa     <NA>
## 26           5.0         3.0          1.6         0.2     setosa     <NA>
## 27           5.0         3.4          1.6         0.4     setosa     <NA>
## 28           5.2         3.5          1.5         0.2     setosa     <NA>
## 29           5.2         3.4          1.4         0.2     setosa     <NA>
## 30           4.7         3.2          1.6         0.2     setosa     <NA>
## 31           4.8         3.1          1.6         0.2     setosa     <NA>
## 32           5.4         3.4          1.5         0.4     setosa     <NA>
## 33           5.2         4.1          1.5         0.1     setosa     <NA>
## 34           5.5         4.2          1.4         0.2     setosa     <NA>
## 35           4.9         3.1          1.5         0.2     setosa     <NA>
## 36           5.0         3.2          1.2         0.2     setosa     <NA>
## 37           5.5         3.5          1.3         0.2     setosa     <NA>
## 38           4.9         3.6          1.4         0.1     setosa     <NA>
## 39           4.4         3.0          1.3         0.2     setosa     <NA>
## 40           5.1         3.4          1.5         0.2     setosa     <NA>
## 41           5.0         3.5          1.3         0.3     setosa     <NA>
## 42           4.5         2.3          1.3         0.3     setosa     <NA>
## 43           4.4         3.2          1.3         0.2     setosa     <NA>
## 44           5.0         3.5          1.6         0.6     setosa     <NA>
## 45           5.1         3.8          1.9         0.4     setosa     <NA>
## 46           4.8         3.0          1.4         0.3     setosa     <NA>
## 47           5.1         3.8          1.6         0.2     setosa     <NA>
## 48           4.6         3.2          1.4         0.2     setosa     <NA>
## 49           5.3         3.7          1.5         0.2     setosa     <NA>
## 50           5.0         3.3          1.4         0.2     setosa     <NA>
## 51           7.0         3.2          4.7         1.4 versicolor    versi
## 52           6.4         3.2          4.5         1.5 versicolor    versi
## 53           6.9         3.1          4.9         1.5 versicolor    versi
## 54           5.5         2.3          4.0         1.3 versicolor    versi
## 55           6.5         2.8          4.6         1.5 versicolor    versi
## 56           5.7         2.8          4.5         1.3 versicolor    versi
## 57           6.3         3.3          4.7         1.6 versicolor    versi
## 58           4.9         2.4          3.3         1.0 versicolor    versi
## 59           6.6         2.9          4.6         1.3 versicolor    versi
## 60           5.2         2.7          3.9         1.4 versicolor    versi
## 61           5.0         2.0          3.5         1.0 versicolor    versi
## 62           5.9         3.0          4.2         1.5 versicolor    versi
## 63           6.0         2.2          4.0         1.0 versicolor    versi
## 64           6.1         2.9          4.7         1.4 versicolor    versi
## 65           5.6         2.9          3.6         1.3 versicolor    versi
## 66           6.7         3.1          4.4         1.4 versicolor    versi
## 67           5.6         3.0          4.5         1.5 versicolor    versi
## 68           5.8         2.7          4.1         1.0 versicolor    versi
## 69           6.2         2.2          4.5         1.5 versicolor    versi
## 70           5.6         2.5          3.9         1.1 versicolor    versi
## 71           5.9         3.2          4.8         1.8 versicolor    versi
## 72           6.1         2.8          4.0         1.3 versicolor    versi
## 73           6.3         2.5          4.9         1.5 versicolor    versi
## 74           6.1         2.8          4.7         1.2 versicolor    versi
## 75           6.4         2.9          4.3         1.3 versicolor    versi
## 76           6.6         3.0          4.4         1.4 versicolor    versi
## 77           6.8         2.8          4.8         1.4 versicolor    versi
## 78           6.7         3.0          5.0         1.7 versicolor    versi
## 79           6.0         2.9          4.5         1.5 versicolor    versi
## 80           5.7         2.6          3.5         1.0 versicolor    versi
## 81           5.5         2.4          3.8         1.1 versicolor    versi
## 82           5.5         2.4          3.7         1.0 versicolor    versi
## 83           5.8         2.7          3.9         1.2 versicolor    versi
## 84           6.0         2.7          5.1         1.6 versicolor    versi
## 85           5.4         3.0          4.5         1.5 versicolor    versi
## 86           6.0         3.4          4.5         1.6 versicolor    versi
## 87           6.7         3.1          4.7         1.5 versicolor    versi
## 88           6.3         2.3          4.4         1.3 versicolor    versi
## 89           5.6         3.0          4.1         1.3 versicolor    versi
## 90           5.5         2.5          4.0         1.3 versicolor    versi
## 91           5.5         2.6          4.4         1.2 versicolor    versi
## 92           6.1         3.0          4.6         1.4 versicolor    versi
## 93           5.8         2.6          4.0         1.2 versicolor    versi
## 94           5.0         2.3          3.3         1.0 versicolor    versi
## 95           5.6         2.7          4.2         1.3 versicolor    versi
## 96           5.7         3.0          4.2         1.2 versicolor    versi
## 97           5.7         2.9          4.2         1.3 versicolor    versi
## 98           6.2         2.9          4.3         1.3 versicolor    versi
## 99           5.1         2.5          3.0         1.1 versicolor    versi
## 100          5.7         2.8          4.1         1.3 versicolor    versi
## 101          6.3         3.3          6.0         2.5  virginica     virg
## 102          5.8         2.7          5.1         1.9  virginica     virg
## 103          7.1         3.0          5.9         2.1  virginica     virg
## 104          6.3         2.9          5.6         1.8  virginica     virg
## 105          6.5         3.0          5.8         2.2  virginica     virg
## 106          7.6         3.0          6.6         2.1  virginica     virg
## 107          4.9         2.5          4.5         1.7  virginica     virg
## 108          7.3         2.9          6.3         1.8  virginica     virg
## 109          6.7         2.5          5.8         1.8  virginica     virg
## 110          7.2         3.6          6.1         2.5  virginica     virg
## 111          6.5         3.2          5.1         2.0  virginica     virg
## 112          6.4         2.7          5.3         1.9  virginica     virg
## 113          6.8         3.0          5.5         2.1  virginica     virg
## 114          5.7         2.5          5.0         2.0  virginica     virg
## 115          5.8         2.8          5.1         2.4  virginica     virg
## 116          6.4         3.2          5.3         2.3  virginica     virg
## 117          6.5         3.0          5.5         1.8  virginica     virg
## 118          7.7         3.8          6.7         2.2  virginica     virg
## 119          7.7         2.6          6.9         2.3  virginica     virg
## 120          6.0         2.2          5.0         1.5  virginica     virg
## 121          6.9         3.2          5.7         2.3  virginica     virg
## 122          5.6         2.8          4.9         2.0  virginica     virg
## 123          7.7         2.8          6.7         2.0  virginica     virg
## 124          6.3         2.7          4.9         1.8  virginica     virg
## 125          6.7         3.3          5.7         2.1  virginica     virg
## 126          7.2         3.2          6.0         1.8  virginica     virg
## 127          6.2         2.8          4.8         1.8  virginica     virg
## 128          6.1         3.0          4.9         1.8  virginica     virg
## 129          6.4         2.8          5.6         2.1  virginica     virg
## 130          7.2         3.0          5.8         1.6  virginica     virg
## 131          7.4         2.8          6.1         1.9  virginica     virg
## 132          7.9         3.8          6.4         2.0  virginica     virg
## 133          6.4         2.8          5.6         2.2  virginica     virg
## 134          6.3         2.8          5.1         1.5  virginica     virg
## 135          6.1         2.6          5.6         1.4  virginica     virg
## 136          7.7         3.0          6.1         2.3  virginica     virg
## 137          6.3         3.4          5.6         2.4  virginica     virg
## 138          6.4         3.1          5.5         1.8  virginica     virg
## 139          6.0         3.0          4.8         1.8  virginica     virg
## 140          6.9         3.1          5.4         2.1  virginica     virg
## 141          6.7         3.1          5.6         2.4  virginica     virg
## 142          6.9         3.1          5.1         2.3  virginica     virg
## 143          5.8         2.7          5.1         1.9  virginica     virg
## 144          6.8         3.2          5.9         2.3  virginica     virg
## 145          6.7         3.3          5.7         2.5  virginica     virg
## 146          6.7         3.0          5.2         2.3  virginica     virg
## 147          6.3         2.5          5.0         1.9  virginica     virg
## 148          6.5         3.0          5.2         2.0  virginica     virg
## 149          6.2         3.4          5.4         2.3  virginica     virg
## 150          5.9         3.0          5.1         1.8  virginica     virg
str(irisifelse)
## 'data.frame':    150 obs. of  6 variables:
##  $ Sepal.Length: num  5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
##  $ Sepal.Width : num  3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...
##  $ Petal.Length: num  1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
##  $ Petal.Width : num  0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
##  $ Species     : Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ Species2    : Factor w/ 2 levels "versi","virg": NA NA NA NA NA NA NA NA NA NA ...