Getting minimum value of a column according a factor column of a dataframe
Dear Rui; Thank you very much. Both of your codes worked correctly. Now I can see the whole row's value. But I found a problem in the results. When I run your codes, the results are shown in a sorted table. I do not know why the results have been sorted according to the "Code" column, smallest to largest. Is there any way to get the results like their order in the first data frame (bilan2)? I used your codes as follow:
bilan3 <- lapply(split(bilan2, bilan2$Code), \(x) x[which.min(x$Q),]) bilan3 = data.frame(do.call(rbind, bilan3))
Sincerely
On Thu, Aug 25, 2022 at 11:52 AM Rui Barradas <ruipbarradas at sapo.pt> wrote:
Hello, OK, what about res <- lapply(split(df1, df1$Code), \(x) x[which.min(x$Q),]) do.call(rbind, res) # Code Y M D Q N O # 41003 41003 81 1 19 0.160 7.17 2.50 # 41005 41005 79 8 17 0.210 5.50 7.20 # 41009 41009 79 2 21 0.218 5.56 4.04 # 41017 41017 79 10 20 0.240 5.30 7.10 A dplyr solution. suppressPackageStartupMessages(library(dplyr)) df1 %>% group_by(Code) %>% slice_min(Q) %>% slice_head(n = 1) # # A tibble: 4 ? 7 # # Groups: Code [4] # Code Y M D Q N O # <fct> <int> <int> <int> <dbl> <dbl> <dbl> # 1 41003 81 1 19 0.16 7.17 2.5 # 2 41005 79 8 17 0.21 5.5 7.2 # 3 41009 79 2 21 0.218 5.56 4.04 # 4 41017 79 10 20 0.24 5.3 7.1 Hope this helps, Rui Barradas ?s 05:56 de 25/08/2022, javad bayat escreveu:
Dear all, Many thanks for your suggested methods and codes, but unfortunately they did not give the desired results. All the codes you have provided are correct but they did not represent
the
whole row which is related to the minimum of "Q".
The code must result in 4 rows, with the minimum value of "Q" and other
column values, as below:
Code
Y
M
D
Q
N
O
41003
81
1
19
0.16
7.17
2.5
41005
79
8
17
0.21
5.5
7.2
41009
79
2
21
0.218
5.56
4.04
41017 79 10 20 0.24 5.3 7.1
Sincerely
41017 79 10 20 0.24 5.3 7.1
On Wed, Aug 24, 2022 at 9:24 PM Rui Barradas <ruipbarradas at sapo.pt>
wrote:
Hello,
Here are two options, the 1st outputs a vector, the 2nd a data.frame.
x<-'41003 81 1 19 0.16 7.17 2.5
41003 77 9 22 0.197 6.8 2.2
41003 79 7 28 0.21 4.7 6.2
41005 79 8 17 0.21 5.5 7.2
41005 80 10 30 0.21 6.84 2.6
41005 80 12 20 0.21 6.84 2.4
41005 79 6 14 0.217 5.61 3.55
41009 79 2 21 0.218 5.56 4.04
41009 79 5 27 0.218 6.4 3.12
41009 80 11 29 0.22 6.84 2.8
41009 78 5 28 0.232 6 3.2
41009 81 8 20 0.233 6.39 1.6
41009 79 9 30 0.24 5.6 7.5
41017 79 10 20 0.24 5.3 7.1
41017 80 7 30 0.24 6.73 2.6'
df1 <- read.table(textConnection(x))
names(df1) <- scan(what = character(),
text = 'Code Y M D Q N O')
df1$Code <- factor(df1$Code)
# 1st option
with(df1, tapply(Q, Code, min))
# 41003 41005 41009 41017
# 0.160 0.210 0.218 0.240
# 2nd option
aggregate(Q ~ Code, df1, min)
# Code Q
# 1 41003 0.160
# 2 41005 0.210
# 3 41009 0.218
# 4 41017 0.240
Hope this helps,
Rui Barradas
?s 08:44 de 24/08/2022, javad bayat escreveu:
Dear all; I am trying to get the minimum value of a column based on a factor
column
of the same data frame. My data frame is like the below:
Code Y M D
Q
N O
41003 81 1 19 0.16 7.17 2.5
41003 77 9 22 0.197 6.8 2.2
41003 79 7 28 0.21 4.7 6.2
41005 79 8 17 0.21 5.5 7.2
41005 80 10 30 0.21 6.84 2.6
41005 80 12 20 0.21 6.84 2.4
41005 79 6 14 0.217 5.61 3.55
41009 79 2 21 0.218 5.56 4.04
41009 79 5 27 0.218 6.4 3.12
41009 80 11 29 0.22 6.84 2.8
41009 78 5 28 0.232 6 3.2
41009 81 8 20 0.233 6.39 1.6
41009 79 9 30 0.24 5.6 7.5
41017 79 10 20 0.24 5.3 7.1
41017 80 7 30 0.24 6.73 2.6
I want to get the minimum value of the "Q" column with the whole row
values, according to the "Code" column which is a factor. Overall it
will
give me 4 rows, with the value of "Q". Below is a code that I used but
it
did not give me what I wanted.
x[which(x$Q == min(x$Q)),]
Sincerely
Best Regards Javad Bayat M.Sc. Environment Engineering Alternative Mail: bayat194 at yahoo.com [[alternative HTML version deleted]]