Formulas and formatted numbers

Jenny Bryan

2018-06-28

Preliminaries

Load googlesheets and dplyr, from which we use the %>% pipe operator and which gives us nicer printing of data frames (tbl_dfs)

library(googlesheets)
suppressMessages(library(dplyr))

TL;DR

To see how your data comes in as a data frame without numeric formatting, try this:

gs_read(..., literal = FALSE)

The googlesheets package comes with functions to access a public Sheet with formulas and formatted numbers. Visit it in the browser or check out this screenshot.

We use it to demo the effect of literal in gs_read(). First we accept the default, which is literal = TRUE.

gs_ff() %>% 
  gs_read(range = cell_cols("B:C"))
#> Accessing worksheet titled 'Sheet1'.
#> Parsed with column specification:
#> cols(
#>   number_formatted = col_character(),
#>   number_rounded = col_double()
#> )
#> # A tibble: 5 x 2
#>   number_formatted number_rounded
#>   <chr>                     <dbl>
#> 1 654,321                    1.23
#> 2 12.34%                     2.35
#> 3 1.23E+09                   3.46
#> 4 3 1/7                      4.57
#> 5 $0.36                      5.68

See the problem? Numeric formatting causes the first column to come in as character.

Try again with literal = FALSE:

gs_ff() %>% 
  gs_read(literal = FALSE, range = cell_cols("B:C"))
#> Accessing worksheet titled 'Sheet1'.
#> Parsed with column specification:
#> cols(
#>   number_formatted = col_double(),
#>   number_rounded = col_double()
#> )
#> # A tibble: 5 x 2
#>   number_formatted number_rounded
#>              <dbl>          <dbl>
#> 1       654321               1.23
#> 2            0.123           2.35
#> 3   1234567890               3.46
#> 4            3.14            4.57
#> 5            0.36            5.68

Fixed it! First column is numeric. And we’ve also gained precision in the second column, previously lost to rounding.

If you want full access to cell contents, use gs_read_cellfeed(..., literal = FALSE) to get a data frame with one per cell. Then take your pick from value, input_value, and numeric_value. Here’s an example with lots of formulas:

gs_ff() %>% 
  gs_read_cellfeed(range = cell_cols("E")) %>% 
  select(-cell_alt, -row, -col) %>% 
  knitr::kable()
#> Accessing worksheet titled 'Sheet1'.
cell value input_value numeric_value
E1 formula formula NA
E2 Google =HYPERLINK(“http://www.google.com/”,“Google”) NA
E3 1,271,591.00 =sum(R[-1]C[-4]:R[3]C[-4]) 1271591.0
E4 =IMAGE(“https://www.google.com/images/srpr/logo3w.png”) NA
E5 $A$1 =ADDRESS(1,1) NA
E6 =SPARKLINE(R[-4]C[-4]:R[0]C[-4]) NA

Read on if you want to know more.

Different notions of cell contents

When working with Google Sheets via the cell feed, there are three ways to define cell contents:

Vocabulary: there’s formatting and then there’s formatting

Click on the Format menu in Google Sheets and you’ll gain access to a “Number” sub-menu and … lots of other stuff. Let’s agree that “formatting” can mean two different things:

Decorative formatting is completely invisible to the Sheets API. It is also a terrible idea to encode data in decorative formatting, though it can be used to visually reinforce information that is properly stored in data (Google Sheets is capable of conditional formatting). Nothing in googlesheets or the rest of this vignette addresses decorative formatting. We shall not speak of it again. From now on, “formatting” means numeric formatting.

A worthy challenge

We’ve created a formula and formatting nightmare sampler Sheet. Go visit it in the browser!. Or check out this screenshot.

gs-test-formula-formatting-screenshot

gs-test-formula-formatting-screenshot

It’s one of the built-in example sheets. Access it with various functions that start with gs_ff.

Here’s how it comes in as a data frame by default: you get “literal values” (suppressing a boring column in order to show the interesting ones).

gs_ff() %>% 
  gs_read() %>% 
  select(-integer)
#> Accessing worksheet titled 'Sheet1'.
#> Parsed with column specification:
#> cols(
#>   integer = col_double(),
#>   number_formatted = col_character(),
#>   number_rounded = col_double(),
#>   character = col_character(),
#>   formula = col_character(),
#>   formula_formatted = col_character()
#> )
#> # A tibble: 5 x 5
#>   number_formatted number_rounded character formula      formula_formatted
#>   <chr>                     <dbl> <chr>     <chr>        <chr>            
#> 1 654,321                    1.23 one       Google       3.18E+05         
#> 2 12.34%                     2.35 <NA>      1,271,591.00 52.63%           
#> 3 1.23E+09                   3.46 three     <NA>         0.22             
#> 4 3 1/7                      4.57 four      $A$1         123,456.00       
#> 5 $0.36                      5.68 five      <NA>         317,898

What if you want unformatted numbers? What if you want the actual formulas? You can now get them the cell feed, which, in googlesheets, means you must use gs_read_cellfeed(). You can cause gs_read() to consult the cell feed by specifying literal = FALSE.

The cell feed

Default methods of reading Sheet data assume that the data occupies a neat rectangle in the upper left corner, that you want all of it, and that you want the literal values.

What if you need more control over which cells? What if you want input or numeric values? Use the cell feed via gs_read_cellfeed(). Under the hood, gs_read() will use the cell feed whenever a cell range is provided, i.e. when the call is like gs_read(..., range = "B4:D9") or gs_read(..., range = cell_cols(4:6)), or when the new argument literal = FALSE.

gs_read_cellfeed() has been extended. As before, we return a data frame with one row per cell, but now we return all 3 notions of cell contents:

cf <- gs_read_cellfeed(gs_ff())
#> Accessing worksheet titled 'Sheet1'.
gs-test-formula-formatting-screenshot

gs-test-formula-formatting-screenshot

cell value input_value numeric_value
A1 integer integer NA
A2 123456 123456 123456.0
A3 345678 345678 345678.0
A4 234567 234567 234567.0
A6 567890 567890 567890.0
B1 number_formatted number_formatted NA
B2 654,321 654321 654321.0
B3 12.34% 12.34% 0.1234
B4 1.23E+09 1234567890 1.23456789E9
B5 3 1/7 3.14159265359 3.14159265359
B6 $0.36 0.36 0.36
C1 number_rounded number_rounded NA
C2 1.23 1.2345 1.2345
C3 2.35 2.3456 2.3456
C4 3.46 3.4567 3.4567
C5 4.57 4.5678 4.5678
C6 5.68 5.6789 5.6789
D1 character character NA
D2 one one NA
D4 three three NA
D5 four four NA
D6 five five NA
E1 formula formula NA
E2 Google =HYPERLINK(“http://www.google.com/”,“Google”) NA
E3 1,271,591.00 =sum(R[-1]C[-4]:R[3]C[-4]) 1271591.0
E4 =IMAGE(“https://www.google.com/images/srpr/logo3w.png”) NA
E5 $A$1 =ADDRESS(1,1) NA
E6 =SPARKLINE(R[-4]C[-4]:R[0]C[-4]) NA
F1 formula_formatted formula_formatted NA
F2 3.18E+05 =average(R[0]C[-5]:R[4]C[-5]) 317897.75
F3 52.63% =R[-1]C[-5]/R[1]C[-5] 0.5263144432081239
F4 0.22 =R[-2]C[-5]/R[2]C[-5] 0.21739421366813996
F5 123,456.00 =min(R[-3]C[-5]:R[1]C[-5]) 123456.0
F6 317,898 =average(R2C1:R6C1) 317897.75
gs-test-formula-formatting-screenshot

gs-test-formula-formatting-screenshot

Exploration of cell contents

We explore the different cell contents for different variables. This motivates the logic behind what happens when gs_read(..., literal = FALSE) and gs_simply_cellfeed(..., literal = FALSE).

Formatted numbers

Column 2, number_formatted, holds variously formatted numbers. It is quite pathological, because in real life numeric formatting is likely to be uniform within a column, which helps readr make good decisions about type conversion.

  • value (what you get by default) imports as character. Not good.
  • input_value is attractive for the first number, because an integer looks like an integer, which is ultimately good for type conversion. But this variable still imports as character, because of the percent sign.
  • numeric_value is usually what you want for numbers.

Logic for cell contents when literal = FALSE

Based on the above examples (and more), here’s the current logic for which cell contents are used in gs_read(..., literal = FALSE) and gs_reshape_cellfeed(..., literal = FALSE). The goal is to create an input that gives the desired result most often with default behavior of readr::type_convert(). If you think this is wrong, please discuss in an issue.