matrix addition - Multiple unique identifiers - r

AM trying to add elements from two different matrices, Each of the matrix has got three unique identifiers as below:
Matrix A:
A B C D E F G H
1 x 1 2 10 11 12 13 10
2 y 1 2 11 12 14 12 13
3 y 1 3 12 10 11 12
The second matrix look like:
A B C D E F G H
1 x 1 2 20 14 17 10 10
2 y 1 2 11 12 14 12 13
3 y 1 3 17 10 19 12
Please note that the variables A, B, and D form unique identifiers for each of the participants.
I would wish to write a code so that as I sum the matrix values I consider this.

You should your data in the long format.
library(reshape2)
dat.l <- melt(dat,id=c('A','B','D'))
dat1.l <- melt(dat1,id=c('A','B','D'))
Then you just sum value :
dat.l$value = dat.l$value + dat1.l$value

Related

extract specefic colum based on character value in a row

I have a data that contains character in the first row like this
J K L M N O P
A T F T F F F T
B 14 15 10 2 3 4 78
C 10 47 15 9 6 12 12
D 17 44 17 1 0 15 11
E 3 12 14 3 2 15 17
i want to extract only the columns that contain the value "T" in row A
so the result i want is this :
J L P
A T T T
B 14 10 78
C 10 15 12
D 17 17 11
E 3 14 17
also, in second time, i want to know how to do the same thing using two conditions, for example : extract all columns that contain value "T" in column A and value 17 in row D so the result will be :
J L
A T T
B 14 10
C 10 15
D 17 17
E 3 14
Thank you
Here is your answer.
> df <- df[, df["A",] == "T" & df["D",] == 17]
You can use index to filter columns. It supports logical statements and you can combine them with &.

R : Change name of variable using for loop

I have a data, and vectors conatin name of variables, from these vectorsi calculate the sum of variables contained in the vector and i want to put the result in a new variables that have diffrent names
let say i have three vectors
>data
Name A B C D E
r1 1 5 12 21 15
r2 2 4 7 10 9
r3 5 15 6 9 6
r4 7 8 0 7 18
And i have these vectors that are generated using for loop that are in variable vec
V1 <- ("A","B","C")
V2 <- ("B","D")
V3 <- ("D","E")
Edit 1 :
These vector are generated using for loop and i don't know the vectors that will be generated or the elemnts contained in these vector , here i'm giving just an example , i want to calculate the sum of variables in each vector and make the result in new variable in my data frame
The issue is don't know how to give new name to variables created (that contains the sum of each vector)
data$column[j] <- rowSums(all_data_Second_program[,vec])
j <- j+1
To obtain this result for example
Name A B C Column1 D Column2 E Column3
r1 1 5 12 18 21 26 15 36
r2 2 4 7 13 10 14 9 19
r3 5 15 6 26 9 24 6 15
r4 7 8 0 15 7 15 18 25
But i didn't obtain this result
Please tell me if you need any more informations or clarifications
Can you tell me please how to that
Put the vectors in a list and then you can use rowSums in lapply -
list_vec <- list(c("A","B","C"), c("B","D"), c("D","E"))
new_cols <- paste0('Column', seq_along(list_vec))
data[new_cols] <- lapply(list_vec, function(x) rowSums(data[x]))
data
# Name A B C D E Column1 Column2 Column3
#1 r1 1 5 12 21 15 18 26 36
#2 r2 2 4 7 10 9 13 14 19
#3 r3 5 15 6 9 6 26 24 15
#4 r4 7 8 0 7 18 15 15 25
We may use a for loop
for(i in 1:3) {
data[[paste0('Column', i)]] <- rowSums(data[get(paste0('V', i))],
na.rm = TRUE)
}
-output
> data
Name A B C D E Column1 Column2 Column3
1 r1 1 5 12 21 15 18 26 36
2 r2 2 4 7 10 9 13 14 19
3 r3 5 15 6 9 6 26 24 15
4 r4 7 8 0 7 18 15 15 25

Merging and summarizing two dataframes

I have the following data:
a <- data.frame(ID=c("A","B","Z","H"), a=c(0,1,2,45), b=c(3,4,5,22), c=c(6,7,8,3))
> a
ID a b c
1 A 0 3 6
2 B 1 4 7
3 Z 2 5 8
4 H 45 22 3
b <- data.frame(ID=c("A","B","E","W","Z","H"), a=c(9,10,11,39,5,0), b=c(4,2,7,54,12,34), c=c(12,0,34,23,13,14))
> b
ID a b c
1: A 9 4 12
2: B 10 2 0
3: E 11 7 34
4: W 39 54 23
5: Z 5 12 13
6: H 0 34 14
I want to merge both dataframes, keeping only rows of data.frame a and summarize the same columns, so at the end I get:
> z
ID a b c
1 A 9 7 18
2 B 11 6 7
3 Z 7 17 21
4 H 45 56 17
So far I have tried the following:
merge(a,b,by="ID",all.x=T,all.y=F)
> merge(a,b,by="ID",all.x=T,all.y=F)
ID a.x b.x c.x a.y b.y c.y
1 A 0 3 6 9 4 12
2 B 1 4 7 10 2 0
3 H 45 22 3 0 34 14
4 Z 2 5 8 5 12 13
> join(a,b,type="left",by="ID")
ID a b c a b c
1 A 0 3 6 9 4 12
2 B 1 4 7 10 2 0
3 Z 2 5 8 5 12 13
4 H 45 22 3 0 34 14
I cannot manage to summarize the columns.
My dataframe is pretty big so if the solution can speed up things that would even be better.
If your data.frame is very big, then you may consider this option:
library(data.table)
## convert data.frame to data.table
setDT(a)
## convert data.frame to data.table
setDT(b)
## merge the two data.tables
c <- merge(a,b,by='ID')
## extract names of all columns except the first one i.e. ID
col_names <- colnames(a)[-1]
## query building
col_1 <- paste0(col_names,'.x')
col_2 <- paste0(col_names,'.y')
cols <- paste(col_1,col_2,sep=',')
cols_2 <- paste0(col_names," = sum(",cols,")")
cols_3 <- paste(cols_2,collapse=',')
query <- paste0("z <- c[,.(",cols_3,"),by=ID]")
## query execution
eval(parse(text = query))
This works at least for your example:
a <- data.frame(ID=c("A","B","Z","H"), a=c(0,1,2,45), b=c(3,4,5,22), c=c(6,7,8,3))
b <- data.frame(ID=c("A","B","E","W","Z","H"), a=c(9,10,11,39,5,0), b=c(4,2,7,54,12,34), c=c(12,0,34,23,13,14))
match_a <- na.omit(match(b$ID, a$ID))
match_b <- na.omit(match(a$ID, b$ID))
df <- cbind(ID = a$ID[match_a], a[match_a, -1] + b[match_b, -1])
First, get matching rows from a in b and vice versa, so we can be sure that we only have those rows that appear in both data frames (and we now know their row-indices in both data frames). Then, simply use vectorized additions for those matching rows, but omit ID, as factor cannot be summed up; add ID back manually.
You cannot directly add both data frame is because both the data frames are of unequal size. To make them of equal size you can check for IDs in a which are present in b and then add them element wise.
new <- b[b$ID %in% a$ID, ]
cbind(ID = a$ID, a[-1] + new[-1])
# ID a b c
#1 A 9 7 18
#2 B 11 6 7
#3 Z 7 17 21
#4 H 45 56 17

Computing values for R dataFrame cells without using for loops

I have a R dataFrame with the followings:
Serial N year current Average
B 10 14 15
B 10 16 15
C 12 13 12
D 40 20 20
B 11 15 15
C 12 11 12
I would like to have a new column based on the average for a unique serial number. I would like to have something like :
Serial N year current Average temp
B 10 14 15 (15+12+20)/15
B 10 16 15 (15+12+20)/15
C 12 13 12 (15+12+20)/12
D 40 20 20 (15+12+20)/20
B 11 15 15 (15+12+20)/15
C 12 11 12 (15+12+20)/12
temp column is the addition of the average value for each Serial N ( for B,C and D) over the value of the average for that row. How can I computing it without using for loops as rows 1,2 and 5 (Serial N: B) is the same in terms of Average column and temp? I started with this:
for (i in unique(df$Serial_N))
{
.........
}
but I got stuck as I also need the average for other Serial N. How can I do this?
For example, you can try something like the following (assuming your computation matches):
df$temp <- sum(tapply(df$Average, df$SerialN, mean)) / df$Average
Resulting output:
SerialN year current Average temp
1 B 10 14 15 3.133333
2 B 10 16 15 3.133333
3 C 12 13 12 3.916667
4 D 40 20 20 2.350000
5 B 11 15 15 3.133333
6 C 12 11 12 3.916667
Using unique.data.frame() can avoid repeat in Average between different groups
df$temp <- sum((unique.data.frame(df[c("Serial_N","Average")]))$Average) / df$Average
In base R, you can use either
df <- transform(df, temp = sum(tapply(df$Average, df$Serial_N, unique))/df$Average)
or
df$temp <- sum(tapply(df$Average, df$Serial_N, unique))/df$Average
both of which will give you
df
# Serial_N year current Average temp
# 1 B 10 14 15 3.133333
# 2 B 10 16 15 3.133333
# 3 C 12 13 12 3.916667
# 4 D 40 20 20 2.350000
# 5 B 11 15 15 3.133333
# 6 C 12 11 12 3.916667
tapply splits df$Average by the levels of df$Serial_N, and then calls unique on them, which gives you a single average for each group, which you can then sum and divide. transform adds a column (equivalent to dplyr::mutate).

How to sum over diagonals of data frame

Say that I have this data frame:
1 2 3 4
100 8 12 5 14
99 1 6 4 3
98 2 5 4 11
97 5 3 7 2
In this above data frame, the values indicate counts of how many observations take on (100, 1), (99, 1), etc.
In my context, the diagonals have the same meanings:
1 2 3 4
100 A B C D
99 B C D E
98 C D E F
97 D E F G
How would I sum across the diagonals (i.e., sum the counts of the like letters) in the first data frame?
This would produce:
group sum
A 8
B 13
C 13
D 28
E 10
F 18
G 2
For example, D is 5+5+4+14
You can use row() and col() to identify row/column relationships.
m <- read.table(text="
1 2 3 4
100 8 12 5 14
99 1 6 4 3
98 2 5 4 11
97 5 3 7 2")
vals <- sapply(2:8,
function(j) sum(m[row(m)+col(m)==j]))
or (as suggested in comments by ?#thelatemail)
vals <- sapply(split(as.matrix(m), row(m) + col(m)), sum)
data.frame(group=LETTERS[seq_along(vals)],sum=vals)
or (#Frank)
data.frame(vals = tapply(as.matrix(m),
(LETTERS[row(m) + col(m)-1]), sum))
as.matrix() is required to make split() work correctly ...
Another aggregate variation, avoiding the formula interface, which actually complicates matters in this instance:
aggregate(list(Sum=unlist(dat)), list(Group=LETTERS[c(row(dat) + col(dat))-1]), FUN=sum)
# Group Sum
#1 A 8
#2 B 13
#3 C 13
#4 D 28
#5 E 10
#6 F 18
#7 G 2
Another solution using bgoldst's definition of df1 and df2
sapply(unique(c(as.matrix(df2))),
function(x) sum(df1[df2 == x]))
Gives
#A B C D E F G
#8 13 13 28 10 18 2
(Not quite the format that you wanted, but maybe it's ok...)
Here's a solution using stack(), and aggregate(), although it requires the second data.frame contain character vectors, as opposed to factors (could be forced with lapply(df2,as.character)):
df1 <- data.frame(a=c(8,1,2,5), b=c(12,6,5,3), c=c(5,4,4,7), d=c(14,3,11,2) );
df2 <- data.frame(a=c('A','B','C','D'), b=c('B','C','D','E'), c=c('C','D','E','F'), d=c('D','E','F','G'), stringsAsFactors=F );
aggregate(sum~group,data.frame(sum=stack(df1)[,1],group=stack(df2)[,1]),sum);
## group sum
## 1 A 8
## 2 B 13
## 3 C 13
## 4 D 28
## 5 E 10
## 6 F 18
## 7 G 2

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