r - sum of one variable in relation to the values of another variable in a data frame

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r - sum of one variable in relation to the values of another variable in a data frame

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#1 by (4 votes)
#2 by (2 votes)

3

I have a multi-column dataframe. How do I add the values of a column within an element of another variable? I want to do this to summarize the data of each species within each campaign. I have already tried using the summarize function of the plyr package but it did not work. It may be because I've factored in the function incorrectly.

campanha   especie   frequencia
   1          A         2
   1          A         1
   1          A         3
   1          A         5
   1          B         1
   1          B         2
   1          B         1
   1          B         6
   1          B         1
   1          C         3
   1          C         1
   1          C         8
   1          C         4
   2          A         2
   2          A         8
   2          A         4
   2          A         5
   2          B         4
   2          B         2
   2          B         6
   2          B         1
   2          C         3
   2          C         1
   2          C         9

r data.frame soma

asked by anonymous 11.07.2018 / 02:47

2 answers

2

This can be solved with the aggregate function.

res <- aggregate(frequencia ~ campanha + especie, dados, sum)
res
#  campanha especie frequencia
#1        1       A         11
#2        2       A         19
#3        1       B         11
#4        2       B         13
#5        1       C         16
#6        2       C         13

Data in dput () format.

dados <-
structure(list(campanha = c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L), 
    especie = structure(c(1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 
    3L, 3L, 3L, 3L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 3L, 3L, 3L
    ), .Label = c("A", "B", "C"), class = "factor"), frequencia = c(2L, 
    1L, 3L, 5L, 1L, 2L, 1L, 6L, 1L, 3L, 1L, 8L, 4L, 2L, 8L, 4L, 
    5L, 4L, 2L, 6L, 1L, 3L, 1L, 9L)), .Names = c("campanha", 
"especie", "frequencia"), class = "data.frame", row.names = c(NA, 
-24L))

11.07.2018 / 08:24

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score 4 · Accepted Answer

Another way to do this is with the dplyr package:

library(dplyr)
dados %>%
  group_by(campanha, especie) %>%
  summarise(sum(frequencia))
# A tibble: 6 x 3
# Groups:   campanha [?]
  campanha especie 'sum(frequencia)'
     <int> <fct>               <int>
1        1 A                      11
2        1 B                      11
3        1 C                      16
4        2 A                      19
5        2 B                      13
6        2 C                      13

Note that I bundled the data with the group_by function and indicating the collation variables. I then used summarise to indicate that I would like to add the frequencia variable within the created groupings.