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Return the First Element Not Being NA

Source: R/coalesceX.R
coalesceX.Rd

If several vectors are supplied, the evaluation will be elementwise, resp. rowwise if x is a data.frame or a matrix. The first element of the result is the first non NA element of the first elements of all the arguments, the second element of the result is the one of the second elements of all the arguments and so on.
Shorter inputs (of non-zero length) are NOT recycled: if all inputs have length greater than 1, they must have the same length (the function will bark otherwise). If any input has length 1 or 0, all inputs are flattened into a single vector (dropping NULLs) and the first valid element is returned, in the manner of a scalar SQL COALESCE.
The idea is borrowed from SQL. Might sometimes be useful when preparing data in R instead of in SQL.

Usage

coalesceX(..., method = c("is.na", "is.null", "is.finite"), flatten = TRUE)

Arguments

...

the elements to be evaluated. This can either be a single vector, several vectors of same length, a matrix, a data.frame or a list of vectors (of same length). See examples.

method

one out of "is.na" (default), "is.null" or "is.finite". With "is.na", Inf values are treated as valid; with "is.finite" they are skipped. "is.null" operates on the arguments themselves and returns the first one that is not NULL.

flatten

logical, defines whether lists are going to be flattened (default TRUE).

Value

return a single vector of the first non NA element(s) of the given data structure.

See also

is.na(), is.finite()

Other vector.na: isNA(), locf(), naIf(), naReplace()

Examples


coalesceX(c(NA, NA, NA, 5, 3))
#> [1] 5
coalesceX(c(NA, NULL, "a"))
#> [1] "a"
coalesceX(NULL, 5, 3)
#> [1] 5

d.frm <- data.frame(matrix(c(
  1, 2, NA, 4,
  NA, NA, 3, 1,
  NaN, 2, 3, 1,
  NA, Inf, 1, 1), nrow=4, byrow=TRUE)
)

coalesceX(d.frm)
#> [1]   1   3   2 Inf
coalesceX(as.matrix(d.frm))
#> [1]   1   3   2 Inf
coalesceX(d.frm$X1, d.frm$X2, d.frm$X3, d.frm$X4)
#> [1]   1   3   2 Inf
coalesceX(d.frm$X1, d.frm$X2, d.frm$X3, d.frm$X4, method="is.finite")
#> [1] 1 3 2 1
coalesceX(list(d.frm[,1], d.frm[,2]))
#> [1]   1  NA   2 Inf

# returns the first finite element (skips NA, Inf, NaN)
coalesceX(d.frm, method="is.finite")
#> [1] 1 3 2 1

# returns the first argument that is not NULL
coalesceX(NULL, NULL, 7, method = "is.null")
#> [1] 7

# with characters (take care, factors won't work!)
# is.finite does not make sense here...
d.frm <- data.frame(matrix(c(
  "a", "b", NA, "4",
  NA, NA, "g", "m",
  NA_character_,"hfdg", "rr", "m",
  NA, Inf, 1, 1), nrow=4, byrow=TRUE)
, stringsAsFactors = FALSE)

coalesceX(d.frm$X1, d.frm$X2, d.frm$X3, d.frm$X4)
#> [1] "a"    "g"    "hfdg" "Inf" 
coalesceX(d.frm)
#> [1] "a"    "g"    "hfdg" "Inf" 
coalesceX(as.list(d.frm))
#> [1] "a"    "g"    "hfdg" "Inf"