Replace Tabs With Spaces

Finds horizontal tab characters (0x09) in a string and replaces them with the spaces that produce the same horizontal offset.

tabs_as_spaces(
  x,
  tab.stops = getOption("fansi.tab.stops", 8L),
  warn = getOption("fansi.warn", TRUE),
  ctl = "all"
)

Arguments

x

character vector or object coercible to character; any tabs therein will be replaced.

tab.stops

integer(1:n) indicating position of tab stops to use when converting tabs to spaces. If there are more tabs in a line than defined tab stops the last tab stop is re-used. For the purposes of applying tab stops, each input line is considered a line and the character count begins from the beginning of the input line.

warn

TRUE (default) or FALSE, whether to warn when potentially problematic Control Sequences are encountered. These could cause the assumptions fansi makes about how strings are rendered on your display to be incorrect, for example by moving the cursor (see ?fansi). At most one warning will be issued per element in each input vector. Will also warn about some badly encoded UTF-8 strings, but a lack of UTF-8 warnings is not a guarantee of correct encoding (use validUTF8 for that).

ctl

character, which Control Sequences should be treated specially. Special treatment is context dependent, and may include detecting them and/or computing their display/character width as zero. For the SGR subset of the ANSI CSI sequences, and OSC hyperlinks, fansi will also parse, interpret, and reapply the sequences as needed. You can modify whether a Control Sequence is treated specially with the ctl parameter.

• "nl": newlines.

• "c0": all other "C0" control characters (i.e. 0x01-0x1f, 0x7F), except for newlines and the actual ESC (0x1B) character.

• "sgr": ANSI CSI SGR sequences.

• "csi": all non-SGR ANSI CSI sequences.

• "url": OSC hyperlinks

• "osc": all non-OSC-hyperlink OSC sequences.

• "esc": all other escape sequences.

• "all": all of the above, except when used in combination with any of the above, in which case it means "all but".

Value

character, x with tabs replaced by spaces, with elements possibly converted to UTF-8.

Details

Since we do not know of a reliable cross platform means of detecting tab stops you will need to provide them yourself if you are using anything outside of the standard tab stop every 8 characters that is the default.

Note

Non-ASCII strings are converted to and returned in UTF-8 encoding. The ctl parameter only affects which Control Sequences are considered zero width. Tabs will always be converted to spaces, irrespective of the ctl setting.

See also

?fansi for details on how Control Sequences are interpreted, particularly if you are getting unexpected results, unhandled_ctl for detecting bad control sequences.

Examples

string <- '1\t12\t123\t1234\t12345678'
tabs_as_spaces(string)
#> [1] "1       12      123     1234    12345678"
writeLines(
  c(
    '-------|-------|-------|-------|-------|',
    tabs_as_spaces(string)
) )
#> -------|-------|-------|-------|-------|
#> 1       12      123     1234    12345678
writeLines(
  c(
    '-|--|--|--|--|--|--|--|--|--|--|',
    tabs_as_spaces(string, tab.stops=c(2, 3))
) )
#> -|--|--|--|--|--|--|--|--|--|--|
#> 1 12 123   1234  12345678
writeLines(
  c(
    '-|--|-------|-------|-------|',
    tabs_as_spaces(string, tab.stops=c(2, 3, 8))
) )
#> -|--|-------|-------|-------|
#> 1 12 123     1234    12345678