Many Google API requests take a field mask, via a fields parameter, in the URL and/or in the body. field_mask() generates such a field mask from an R list, typically a list that is destined to be part of the body of a request that writes or updates a resource. field_mask() is designed to help in the common case where the attributes you wish to modify are exactly the ones represented in the object. It is possible to use a "larger" field mask, that is either less specific or that explicitly includes other attributes, in which case the attributes covered by the mask but absent from the object are reset to default values. This is not exactly the use case field_mask() is designed for, but its output could still be useful as a first step in constructing such a mask.




A named R list, where the requirement for names applies at all levels, i.e. recursively.


A Google API field mask, as a string.

See also


x <- list(sheetId = 1234, title = "my_favorite_worksheet") field_mask(x)
#> sheetId,title
x <- list( userEnteredFormat = list( backgroundColor = list( red = 159 / 255, green = 183 / 255, blue = 196 / 255 ) ) ) field_mask(x)
#> userEnteredFormat.backgroundColor(red,green,blue)
x <- list( sheetId = 1234, gridProperties = list(rowCount = 5, columnCount = 3) ) field_mask(x)
#> sheetId,gridProperties(rowCount,columnCount)