README.md

In jennybc/cellranger: Translate Spreadsheet Cell Ranges to Rows and Columns

Helper package to support R scripts or packages that interact with spreadsheets.

Installation

Option 1: Install from CRAN:

install.packages("cellranger")

Option 2: Install the development version from GitHub:

# install.packages("devtools")
devtools::install_github("jennybc/cellranger")

What is cellranger for?

Describe a rectangle of cells. For example, what you’ve got is the string “D12:F15” and what you want is an R object that holds the row and column for the upper left and lower right corners of this rectangle. Read below about the cell_limits class. The googlesheets and readODS packages use cellranger to translate user-supplied cell range info into something more programmatically useful.

Handle cell references found in spreadsheet formulas. If you’re parsing unevaluated spreadsheet formulas, use the ra_ref and cell_addr classes for handling absolute, relative, and mixed cell references. Classes inspired by Spreadsheet Implementation Technology from Sestoft (MIT Press, 2014).

Convert between annoying spreadsheet reference formats. Some utility functions are exposed, such as A1_to_R1C1(), which converts from A1 formatted strings to R1C1, and letter_to_num(), which converts a Excel column ID to a number, e.g. column AQZ is more usefully known as column 1144.

Describing rectangles via cell_limits

cellranger provides an S3 class, cell_limits, as the standard way to store a cell range. You can explicitly construct a cell_limits object by specifying the upper left and lower right cells and, optionally, the hosting worksheet:

cell_limits(ul = c(ROW_MIN, COL_MIN), lr = c(ROW_MAX, COL_MAX), sheet = "SHEET")

Think of it like R3C1:R7C4 notation, but with the R and C removed.

More often you’ll get a cell_limits object by sending diverse user input through as.cell_limits(). That’s what’s going on in calls like these from googlesheets:

library(googlesheets)
gs_read(..., range = "D12:F15")
gs_read(..., range = "raw_data!R1C12:R6C15")
gs_read(..., range = cell_limits(c(1, 1), c(6, 15)))
gs_read(..., range = cell_limits(c(2, 1), c(NA, NA)))
gs_read(..., range = cell_rows(1:100))
gs_read(..., range = cell_cols(3:8))
gs_read(..., range = cell_cols("B:MZ"))
gs_read(..., range = anchored("B4", dim = c(2, 10)))
gs_read(..., range = anchored("A1", dim = c(5, 6), col_names = TRUE))
## internal usage in functions that put data into a googlesheet
anchored(input = head(iris))
anchored(input = head(iris), col_names = FALSE)
anchored(input = head(LETTERS))
anchored(input = head(LETTERS), byrow = TRUE)

Read the docs for more information on some specialized helpers:

• Row- or column-only specification: cell_rows(), cell_cols().
• Specification via an object you want to write and, optionally, an anchor cell: anchored()

library("cellranger")
(cl <- as.cell_limits("raw_data!R1C12:R6C15"))
#> <cell_limits (1, 12) x (6, 15) in 'raw_data'>

The dim method reports dimensions of the targetted cell rectangle. as.range() converts a cell_limits object back into an Excel range.

dim(cl)
#> [1] 6 4

as.range(cl)
#> [1] "raw_data!R1C12:R6C15"

as.range(cl, fo = "A1", sheet = FALSE, strict = TRUE)
#> [1] "$L$1:$O$6"

Use NA to leave a limit unspecified, i.e. describe a degenerate rectangle

cell_limits(c(3, 2), c(7, NA))
#> <cell_limits (3, 2) x (7, -)>

If the maximum row or column is specified but the associated minimum is not, then it is set to 1.

cell_limits(c(NA, NA), c(3, 5))
#> <cell_limits (1, 1) x (3, 5)>

Utilities for spreadsheet annoyances

We’ve exposed utility functions which could be useful to anyone manipulating Excel-like references.

## convert character column IDs to numbers ... and vice versa
letter_to_num(c('AA', 'ZZ', 'ABD', 'ZZZ', ''))
#> [1]    27   702   732 18278    NA

num_to_letter(c(27, 702, 732, 18278, 0, -5))
#> [1] "AA"  "ZZ"  "ABD" "ZZZ" NA    NA

## convert between A1 and R1C1 cell references
A1_to_R1C1(c("$A$1", "$AZ$10"))
#> [1] "R1C1"   "R10C52"
A1_to_R1C1(c("A1", "AZ10"), strict = FALSE)
#> [1] "R1C1"   "R10C52"

R1C1_to_A1(c("R1C1", "R10C52"))
#> [1] "$A$1"   "$AZ$10"
R1C1_to_A1(c("R1C1", "R10C52"), strict = FALSE)
#> [1] "A1"   "AZ10"

## detect cell reference formats with
## is_A1() and is_R1C1()
x <- c("A1", "$A4", "$b$12", "RC1", "R[-4]C9", "R5C3")
data.frame(x, A1 = is_A1(x), R1C1 = is_R1C1(x))
#>         x    A1  R1C1
#> 1      A1  TRUE FALSE
#> 2     $A4  TRUE FALSE
#> 3   $b$12  TRUE FALSE
#> 4     RC1  TRUE  TRUE
#> 5 R[-4]C9 FALSE  TRUE
#> 6    R5C3 FALSE  TRUE

## guess format with
## guess_fo()
refs <- c("A1", "$A1", "A$1", "$A$1", "a1",
          "R1C1", "R1C[-1]", "R[-1]C1", "R[-1]C[9]")
data.frame(refs, guessed = guess_fo(refs))
#>        refs guessed
#> 1        A1      A1
#> 2       $A1      A1
#> 3       A$1      A1
#> 4      $A$1      A1
#> 5        a1      A1
#> 6      R1C1    R1C1
#> 7   R1C[-1]    R1C1
#> 8   R[-1]C1    R1C1
#> 9 R[-1]C[9]    R1C1

jennybc/cellranger documentation built on May 19, 2019, 4:04 a.m.