gtools (version 3.9.5)

smartbind: Efficient rbind of data frames, even if the column names don't match

Description

Efficient rbind of data frames, even if the column names don't match

Usage

smartbind(..., list, fill = NA, sep = ":", verbose = FALSE)

Value

The returned data frame will contain:

columns

all columns present in any provided data frame

rows

a set of rows from each provided data frame, with values in columns not present in the given data frame filled with missing (NA) values.

The data type of columns will be preserved, as long as all data frames with a given column name agree on the data type of that column. If the data frames disagree, the column will be converted into a character strings. The user will need to coerce such character columns into an appropriate type.

Arguments

...

Data frames to combine

list

List containing data frames to combine

fill

Value to use when 'filling' missing columns. Defaults to NA.

sep

Character string used to separate column names when pasting them together.

verbose

Logical flag indicating whether to display processing messages. Defaults to FALSE.

Author

Gregory R. Warnes

See Also

rbind, cbind

Examples

df1 <- data.frame(A = 1:10, B = LETTERS[1:10], C = rnorm(10))
df2 <- data.frame(A = 11:20, D = rnorm(10), E = letters[1:10])

# rbind would fail
if (FALSE) {
rbind(df1, df2)
# Error in match.names(clabs, names(xi)) : names do not match previous
# names:
# 	D, E
}
# but smartbind combines them, appropriately creating NA entries
smartbind(df1, df2)

# specify fill=0 to put 0 into the missing row entries
smartbind(df1, df2, fill = 0)
# \dontshow{
n <- 10 # number of data frames to create
s <- 10 # number of rows in each data frame

# create a bunch of column names
names <- LETTERS[2:5]

# create a list 'Z' containing 'n' data frames, each with 3 columns
# and 's' rows.  The first column is always named 'A', but the other
# two have a names randomly selected from 'names'

Z <- list()
for (i in 1:n)
{
  X <- data.frame(
    A = sample(letters, s, replace = TRUE),
    B = letters[1:s],
    C = rnorm(s)
  )
  colnames(X) <- c("A", sample(names, 2, replace = FALSE))
  Z[[i]] <- X
}

# Error in match.names(clabs, names(xi)) : names do not match
# previous names: E

# But smartbind will 'do the right thing'
df <- do.call("smartbind", Z)
df

# Equivalent call:
df <- smartbind(list = Z)
# }