Create a new data frame using values from existing data

Question

I have a data frame that looks like this:

I need to make a new data frame that takes the values for density from the expr_phenotype column and puts them in the formula: ((density for 4 + density for 68)/(density for 0+4+64+68)*100). How should I go about this?

I know it's easier to make a reproducible example but this is a funky dataset.

Please do not provide screen shots of your data. Instead, provide it as text by clicking the [edit] button under your post. Either copy the output of the `dput(head(data))` command and paste the output into your question (preferred) or paste the tab delimited data from a spreadsheet program. Please see [How to make a great R reproducible example](https://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example) for more information. — Ian Campbell, Apr 21 '21 at 04:03
it's not very clear what you are trying to achieve here based on your description. You might consider use `pivot_wider(names_from = expr, values_from = density)` to make the `expr` colum spread out and select the values by their col names. — Kabocha Porter, Apr 21 '21 at 04:16

score 1 · Answer 1 · answered Apr 21 '21 at 04:13

We can use dplyr::group_by, then use summarise:

library(dplyr)
data %>%
   group_by(core_x,core_y) %>%
   summarise(result = sum(density[expr_phenotype %in% c(4,68)])/
                      sum(density[expr_phenotype %in% c(0,4,64,68)]) * 100)
## A tibble: 3 x 3
## Groups:   core_x [1]
#  core_x core_y result
#   <int>  <int>  <dbl>
#1      1      1   39.8
#2      1      2   39.1
#3      1      3   51.8

Data (Obtained by OCR, please forgive errors)

data <- structure(list(core_x = c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L), core_y = c(1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 3L, 3L), core = structure(c(1L, 
1L, 1L, 1L, 2L, 2L, 2L, 2L, 3L, 3L), .Label = c("1--1", "1--2", 
"1--3"), class = "factor"), xX = structure(c(1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L), .Label = "Cc", class = "factor"), phenotype = structure(c(1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L), .Label = "CD163", class = "factor"), 
    expr_phenotype = c(0L, 4L, 64L, 68L, 0L, 4L, 64L, 68L, 0L, 
    4L), count = c(510L, 334L, 1L, 4L, 186L, 116L, 1L, 3L, 196L, 
    210L), density = c(451L, 295L, 1L, 4L, 164L, 103L, 1L, 3L, 
    173L, 186L)), row.names = 3:12, class = "data.frame")

Create a new data frame using values from existing data

1 Answers1