r - 当每行是年/站点/区域时为计数创建宽数据

Question

我正在处理以下格式的数据

Year  Site Zone Species
2010    A   a   cat
2010    A   a   dog
2010    A   b   cat
2010    B   a   rabbit
2010    B   a   cat
2010    B   b   cat
2011    A   a   dog
2011    A   a   cat
2011    A   b   rabbit
2011    B   a   cat
2011    B   b   dog
2011    B   b   cat

我想获得:

Year    Site Zone   cat dog rabbit
2010    A     a     1   1   0
2010    A     b     1   0   0
2010    B     a     1   0   1
2010    B     b     1   0   0
2011    A     a     1   1   0
2011    A     b     0   0   1
2011    B     a     1   0   0
2011    B     b     1   1   0

在 R 中使用 dplyr(或其他方式)执行此操作的最佳方法是什么？

这是长格式数据的dput:

structure(list(Year = c(2010L, 2010L, 2010L, 2010L, 2010L, 2010L, 
2011L, 2011L, 2011L, 2011L, 2011L, 2011L), Site = c("A", "A", 
"A", "B", "B", "B", "A", "A", "A", "B", "B", "B"), Zone = c("a", 
"a", "b", "a", "a", "b", "a", "a", "b", "a", "b", "b"), Species = c("cat", 
"dog", "cat", "rabbit", "cat", "cat", "dog", "cat", "rabbit", 
"cat", "dog", "cat")), class = "data.frame", row.names = c(NA, 
-12L))

Answer 1

使用 pivot_wider -

tidyr::pivot_wider(df, names_from = Species, values_from = Species, 
                   values_fn = length, values_fill = 0)

#   Year Site  Zone    cat   dog rabbit
#  <int> <chr> <chr> <int> <int>  <int>
#1  2010 A     a         1     1      0
#2  2010 A     b         1     0      0
#3  2010 B     a         1     0      1
#4  2010 B     b         1     0      0
#5  2011 A     a         1     1      0
#6  2011 A     b         0     0      1
#7  2011 B     a         1     0      0
#8  2011 B     b         1     1      0

或者用data.table -

library(data.table)
dcast(setDT(df), Year + Site + Zone ~ Species, fun.aggregate = length)