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Split Strings into Multiple Columns

Source: R/strSplitToCol.R
strSplitToCol.Rd

Splits character vectors into multiple columns based on a delimiter. Each element of x is split using strsplit(), and the resulting parts are expanded into separate columns.

Usage

strSplitToCol(x, split = " ", fixed = TRUE, naForm = "", colNames = NULL)

Arguments

x

a character vector or a data frame of character columns to be split. Each element (or column) is processed separately.

split

character string specifying the delimiter for splitting. Passed to strsplit().

fixed

logical; if TRUE, split is used as a fixed string. Otherwise, it is treated as a regular expression.

naForm

character value used to replace missing elements created by unequal split lengths.

colNames

optional character vector specifying column names for the resulting data frame. Recycled if necessary.

Value

a data frame containing the split components of x. Additional attribute:

  • cols: integer vector with number of columns per input element.

Details

All rows are padded to the same number of columns per input element. Missing values are filled with naForm.

For each element (or column) in x, the function:

  1. Splits each entry using strsplit()

  2. Determines the maximum number of split parts

  3. Pads shorter splits with naForm

  4. Combines results into a matrix via rbind()

The final result is a data frame where each original element or column contributes one or more columns depending on the number of splits.

An attribute "cols" is attached, indicating the number of columns generated for each element of x.

See also

Other string.transform: char-ascii-conversion, mGsub(), strSplitToDummy()

Examples

x <- c("A B C", "D E", "F")
strSplitToCol(x)
#>   X1 X2 X3
#> 1  A  B  C
#> 2  D  E   
#> 3  F      

# Custom delimiter
x <- c("A|B|C", "D|E", "F")
strSplitToCol(x, split = "|")
#>   X1 X2 X3
#> 1  A  B  C
#> 2  D  E   
#> 3  F      

# Multiple columns
df <- data.frame(
  a = c("x y", "z"),
  b = c("1 2 3", "4 5"),
  stringsAsFactors = FALSE
)
strSplitToCol(df)
#>   a.1 a.2 b.1 b.2 b.3
#> 1   x   y   1   2   3
#> 2   z       4   5