Find the first non-missing element

Given a set of vectors, coalesce() finds the first non-missing value at each position. It's inspired by the SQL COALESCE function which does the same thing for SQL NULLs.

Usage

coalesce(..., .ptype = NULL, .size = NULL)

Arguments

...

<dynamic-dots>

One or more vectors. These will be recycled against each other, and will be cast to their common type.

.ptype

An optional prototype declaring the desired output type. If supplied, this overrides the common type of the vectors in ....

.size

An optional size declaring the desired output size. If supplied, this overrides the common size of the vectors in ....

Value

A vector with the same type and size as the common type and common size of the vectors in ....

See also

na_if() to replace specified values with an NA. tidyr::replace_na() to replace NA with a value.

Examples

# Use a single value to replace all missing values
x <- sample(c(1:5, NA, NA, NA))
coalesce(x, 0L)
#> [1] 0 0 0 5 4 3 1 2

# The equivalent to a missing value in a list is `NULL`
coalesce(list(1, 2, NULL), list(NA))
#> [[1]]
#> [1] 1
#> 
#> [[2]]
#> [1] 2
#> 
#> [[3]]
#> [1] NA
#> 

# Or generate a complete vector from partially missing pieces
y <- c(1, 2, NA, NA, 5)
z <- c(NA, NA, 3, 4, 5)
coalesce(y, z)
#> [1] 1 2 3 4 5

# Supply lists by splicing them into dots:
vecs <- list(
  c(1, 2, NA, NA, 5),
  c(NA, NA, 3, 4, 5)
)
coalesce(!!!vecs)
#> [1] 1 2 3 4 5