[R] nested for loop with data table

[Jim Lemon]

Hi Ek,
I think you want your example to look like this:

Sample<-read.table(text=
"Num Color Grade Value Month Day
1 yellow A 20 May 1
2 green B 25 June 2
3 green A 10 April 3
4 black A 17 August 3
5 red C 5 December 5
6 orange D 0 January 13
7 orange E 12 January 5
8 orange F 11 February 8
9 orange F 99 July 23
10 orange F 70 May 7
11 black A 77 June 11
12 green B 87 April 33
13 black A 79 August 9
14 green A 68 December 14
15 black C 90 January 31
16 green D 79 January 11
17 black E 101 February 17
18 red F 90 July 21
19 red F 112 February 13
20 red F 101 July 20",
header=TRUE)
AAA<-Sample[Sample$Num < 5 & Sample$Day < 3,]
BBB<-Sample[Sample$Num > 15 & Sample$Day > 13,]
for(i in 1:length(AAA)) {
 for(j in 1:length(BBB)) {
  ...
 }
}

except in data.table notation. However, I can't work out what you want
to do in the loop.

Jim


On Wed, May 3, 2017 at 2:35 AM, Ek Esawi <esawiek at gmail.com> wrote:
> I have a huge data file; a sample is listed below. I am using the package
> data table to process the file and I am stuck on one issue and need some
> feedback. I used fread to create a data table. Then I divided the data
> table (named File1) into 10 general subsets using common table commands
> such as:
>
>
>
> AAA <- File1[Num<5&day>15]
>
> BBB <- File1[Num>15&day<10]
>
> …..
>
> …..
>
> …..
>
> …..
>
> …..
>
> …..
>
>
>
> I wanted to divide and count each of the above subsets based on a set of
> parameters common to all subsets. I did the following to go through each
> subset and it works:
>
> For (I in 1: length (AAA)) {
>
>               aa <- c(AAA[color==”green”&grade==”a”,month==”Januray” .N],[
> AAA[color==”green”&grade==”b”& month==”June”’ .N])
>
> }
>
>
>
> The question: I don’t want to have a separate loop for each subset (10
> loops). Instead, I was hoping to have 2 nested loops in the form below:
>
>
>
> For (I in 1:N)){
>
>               For (j in 1:M){
>
>
>
> }
>
> }
>
>
>
>  Sample
>
>
> Num
>
> Color
>
> Grade
>
> Value
>
> Month
>
> Day
>
> 1
>
> yellow
>
> A
>
> 20
>
> May
>
> 1
>
> 2
>
> green
>
> B
>
> 25
>
> June
>
> 2
>
> 3
>
> green
>
> A
>
> 10
>
> April
>
> 3
>
> 4
>
> black
>
> A
>
> 17
>
> August
>
> 3
>
> 5
>
> red
>
> C
>
> 5
>
> December
>
> 5
>
> 6
>
> orange
>
> D
>
> 0
>
> January
>
> 13
>
> 7
>
> orange
>
> E
>
> 12
>
> January
>
> 5
>
> 8
>
> orange
>
> F
>
> 11
>
> February
>
> 8
>
> 9
>
> orange
>
> F
>
> 99
>
> July
>
> 23
>
> 10
>
> orange
>
> F
>
> 70
>
> May
>
> 7
>
> 11
>
> black
>
> A
>
> 77
>
> June
>
> 11
>
> 12
>
> green
>
> B
>
> 87
>
> April
>
> 33
>
> 13
>
> black
>
> A
>
> 79
>
> August
>
> 9
>
> 14
>
> green
>
> A
>
> 68
>
> December
>
> 14
>
> 15
>
> black
>
> C
>
> 90
>
> January
>
> 31
>
> 16
>
> green
>
> D
>
> 79
>
> January
>
> 11
>
> 17
>
> black
>
> E
>
> 101
>
> February
>
> 17
>
> 18
>
> red
>
> F
>
> 90
>
> July
>
> 21
>
> 19
>
> red
>
> F
>
> 112
>
> February
>
> 13
>
> 20
>
> red
>
> F
>
> 101
>
> July
>
> 20
>
>         [[alternative HTML version deleted]]
>
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