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rnested-loops

Nested Loop in r


I am having trouble writing an algo in r, in python this wouldnt be a big deal but r's syntax has thrown me off. I would like to set the first index of z and nums equal to eachother and put it into a list. Once in a list I would like to print the letter of a negative number. Then i would like to print the numbers that correspond to j k l.

nums<-c(1.0, 3.0, -2, 8, -4, 4, 2, -3, 9, 1, 4, 2, 2, 1, 8, 2)
z<-c("a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p")
lets<-c(j,k,l)
for (i in nums){
for(j in z) {
}}
list=((a,1),(b,3),(c,-2),(d,8),(e,-4),(f,4),(g,2),(h,-3),(i,9),(j,1),(k,4),(l,2),(m,2),(n,1),(o,8),(p,2))

negative=c,e,h,
letters=1,4,2

Solution

  • What you could do is (using your data):

    df <- data.frame(z,nums, stringsAsFactors = FALSE)
    

    There all the letters and nums in

        > df
       z nums
    1  a    1
    2  b    3
    3  c   -2
    4  d    8
    5  e   -4
    6  f    4
    7  g    2
    8  h   -3
    9  i    9
    10 j    1
    11 k    4
    12 l    2
    13 m    2
    14 n    1
    15 o    8
    16 p    2
    

    And then you can access what ever you want:

    df$z[df$nums<0]
    

    Results in:

    [1] "c" "e" "h"
    

    And to get the number for j,k,l you can use grepl:

    df[grepl("[j,k,l]", df$z),]
       z nums
    10 j    1
    11 k    4
    12 l    2
    

    Then you have again a sub data frame or for just the numbers do:

    df$nums[grepl("[j,k,l]", df$z)]
    [1] 1 4 2