R software Pivot data frame without Null-CodePudding

I have looked to all similar question of stackoverflow but without success.

Condiser the iris data set. I just want to put the species as columns, and get below each species names, only the Sepal Length.

So far i get:

library("reshape2")
data(iris)
iris$ID <- 1:nrow(iris)
acast(iris,ID~Species,value.var="Sepal.Length")

The result is almost what i expected... Excepted all the NA that shouldn't be here (each column values should be shifted up to that we get only 50 rows for the whole data frame).

Thanks for your help

CodePudding user response：

Here are couple of options -

library(dplyr)
library(tidyr)

iris %>%
  select(Species, Sepal.Length) %>%
  group_by(Species) %>%
  mutate(row = row_number()) %>%
  pivot_wider(names_from = Species, values_from = Sepal.Length) %>%
  select(-row)

#   setosa versicolor virginica
#    <dbl>      <dbl>     <dbl>
# 1    5.1        7         6.3
# 2    4.9        6.4       5.8
# 3    4.7        6.9       7.1
# 4    4.6        5.5       6.3
# 5    5          6.5       6.5
# 6    5.4        5.7       7.6
# 7    4.6        6.3       4.9
# 8    5          4.9       7.3
# 9    4.4        6.6       6.7
#10    4.9        5.2       7.2
# … with 40 more rows

data.table -

library(data.table)

df <- iris

dcast(setDT(df), rowid(Species)~Species, value.var = "Sepal.Length")

CodePudding user response：

Another possible solution:

library(tidyverse)

iris %>% 
  select(Sepal.Length, Species) %>% 
  pivot_wider(names_from = Species, values_from = Sepal.Length, values_fn = list) %>% 
  unnest(everything())

#> # A tibble: 50 × 3
#>    setosa versicolor virginica
#>     <dbl>      <dbl>     <dbl>
#>  1    5.1        7         6.3
#>  2    4.9        6.4       5.8
#>  3    4.7        6.9       7.1
#>  4    4.6        5.5       6.3
#>  5    5          6.5       6.5
#>  6    5.4        5.7       7.6
#>  7    4.6        6.3       4.9
#>  8    5          4.9       7.3
#>  9    4.4        6.6       6.7
#> 10    4.9        5.2       7.2
#> # … with 40 more rows