Creating a Sequential List of Letters with R

Creating a sequential list of letters with R

This is what you're looking for:

> paste("This_", letters, sep="")

> [1] "This_a" "This_b" "This_c" "This_d" "This_e" "This_f" "This_g" "This_h"
  [9] "This_i" "This_j" "This_k" "This_l" "This_m" "This_n" "This_o" "This_p"
  [17] "This_q" "This_r" "This_s" "This_t" "This_u" "This_v" "This_w" "This_x"
  [25] "This_y" "This_z"

Creating a sequential list of numbers and letters with R

You could use outer

c(t(outer(paste0("var_", 1:2), LETTERS[1:4], paste0)))
#[1] "var_1A" "var_1B" "var_1C" "var_1D" "var_2A" "var_2B" "var_2C" "var_2D"

Or another option with paste0 and rep

paste0(rep(paste0("var_", 1:2), each = 4), LETTERS[1:4])

Generate a sequence of characters from 'A'-'Z'

Use LETTERS and letters (for uppercase and lowercase respectively).

Create a sequence between two letters

This would be another base R option:

letters[(letters >= "b") & (letters <= "f")]
# [1] "b" "c" "d" "e" "f"

R - generate a sequence of letters and numbers

You can do

paste0(rep(LETTERS[1:5], 3), rep(1:3, each = 5))
#> [1] "A1" "B1" "C1" "D1" "E1" "A2" "B2" "C2" "D2" "E2" "A3" "B3" "C3" "D3" "E3"

Create a list of sequential letters like in excel's header in R

In case if you are interested in base R solution, you can try this:

all <- expand.grid(LETTERS, LETTERS)
all <- all[order(all$Var1,all$Var2),]
out <- c(LETTERS, do.call('paste0',all))

The out will return 702 values as vectors, I believe you want to subset them until 559, so you can write: out[1:559].

To rename your columns you can use, where data_frame is your data frame name

names(data_frame) <- out[1:559]

One important note though, I am assuming here that you only wanted column with two characters not more than that.

A generic approach using gtools

 comb <- lapply(1:3, function(x)gtools::permutations(26,x, LETTERS, repeats.allowed = TRUE))
 ## Using 3 for excel 3 combinations of alphabets
 unlist(lapply(comb, function(x)do.call('paste0', data.frame(x,stringsAsFactors = FALSE))))

Some observations:

> out[1:50]
 [1] "A"  "B"  "C"  "D"  "E"  "F"  "G"  "H"  "I"  "J"  "K" 
[12] "L"  "M"  "N"  "O"  "P"  "Q"  "R"  "S"  "T"  "U"  "V" 
[23] "W"  "X"  "Y"  "Z"  "AA" "AB" "AC" "AD" "AE" "AF" "AG"
[34] "AH" "AI" "AJ" "AK" "AL" "AM" "AN" "AO" "AP" "AQ" "AR"
[45] "AS" "AT" "AU" "AV" "AW" "AX"

is there a way to extend LETTERS past 26 characters e.g., AA, AB, AC...?

Would 702 be enough?

LETTERS702 <- c(LETTERS, sapply(LETTERS, function(x) paste0(x, LETTERS)))

If not, how about 18,278?

MOAR_LETTERS <- function(n=2) {
  n <- as.integer(n[1L])
  if(!is.finite(n) || n < 2)
    stop("'n' must be a length-1 integer >= 2")

  res <- vector("list", n)
  res[[1]] <- LETTERS
  for(i in 2:n)
    res[[i]] <- c(sapply(res[[i-1L]], function(y) paste0(y, LETTERS)))

  unlist(res)
}
ml <- MOAR_LETTERS(3)
str(ml)
# chr [1:18278] "A" "B" "C" "D" "E" "F" "G" "H" "I" "J" "K" "L" "M" "N" "O" ...

R: make column with a sequence of letters for all values in another column greater than threshold

We may use

library(data.table)
setDT(df)[number >= threshold, passed := letters[.I]]

create a sequence of numbers written in letters

You can use the english package for this.

library(english)

as.english(100:1)

[1] one hundred   ninety nine   ninety eight  ninety seven  ...  

Or for character output:

words(100:1) 

[1] "one hundred"   "ninety nine"   "ninety eight"  "ninety seven" ...

Edit: As neilfws notes words() will produce character strings which might be more useful if you want to continue to process the data. as.english() is a print/format method.

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