Assigning multiple variables in for loop

Question

I have a piece of code that repeats 7 times and I am trying to condense the code. I am trying to do run a function and the raw_data_* files are dataframes. This is what I am trying to achieve (un-condensed code):

tax_1 <- count_taxa(raw_data_1, "Site_1", "Domain", domain_n)
tax_2 <- count_taxa(raw_data_2, "Site_2", "Domain", domain_n)
tax_3 <- count_taxa(raw_data_3, "Site_3", "Domain", domain_n)
tax_4 <- count_taxa(raw_data_4, "Site_4", "Domain", domain_n)
tax_5 <- count_taxa(raw_data_5, "Site_5", "Domain", domain_n)
tax_6 <- count_taxa(raw_data_6, "Site_6", "Domain", domain_n)
tax_7 <- count_taxa(raw_data_7, "Site_7", "Domain", domain_n)
all_tax <- bind_rows(tax_1, tax_2, tax_3, tax_4, tax_5, tax_6, tax_7)

And I am trying to do something like this:

tax_list <- list(raw_data_1, raw_data_2, raw_data_3, raw_data_4, raw_data_5, raw_data_6, raw_data_7)
site_list <- list("Site_1", "Site_2", "Site_3", "Site_4", "Site_5", "Site_6", "Site_7")

for (tax in tax_list) {

  tax_1 <- count_taxa(tax, site, domain_n)
????

}
all_tax <- bind_rows(tax_1, tax_2, tax_3, tax_4, tax_5, tax_6, tax_7)

But I have no idea if this is even possible. Any ideas?

Try purrr::map2_df(tax_list, site_list, function(x,y) count_taxa(x,y, domain_n)) — A. Suliman

slava-kohut slava-kohut · Accepted Answer · 2019-09-22T20:43:03

You can create an empty list and then add data frames to it as the loop progresses. In the end, you can bind them all into all_tax using Reduce.

tax_list <- list(raw_data_1, raw_data_2, raw_data_3, raw_data_4, raw_data_5, raw_data_6, raw_data_7)
site_list <- list("Site_1", "Site_2", "Site_3", "Site_4", "Site_5", "Site_6", "Site_7")

proc_df <- list()

for (i in seq_along(tax_list)) {
  proc_df <- c(proc_df, count_taxa(tax_list[[i]], site_list[[i]], domain_n))
}

all_tax <- Reduce(rbind, proc_df)

An alternative would be to use a map2_dfr function from purrr:

purrr::map2_dfr(tax_list, site_list, count_taxa, domain_n)

Assigning multiple variables in for loop

1 Answers