s_regex {tinycodet} | R Documentation |
The %s-% and %s/% operators,
as well as the string detection operators (str_truth),
perform pattern matching for some purpose,
where the pattern is given on the right hand side.
When a character vector or string is given on the right hand side,
this is interpreted as case-sensitive
regex
patterns from 'stringi'.
Instead of giving a string or character vector of regex patterns,
one can also supply a list to specify exactly how the pattern should be interpreted.
The list should use the exact same argument convention as 'stringi'.
For example:
list(regex=p, case_insensitive=FALSE, ...)
list(fixed=p, ...)
list(coll=p, ...)
list(charclass=p, ...)
All arguments in the list are simply passed to the
appropriate functions in 'stringi'.
For example:
x %s/% p
counts how often regular expression specified in character vector
p
occurs in x
, whereas the following,
x %s/% list(fixed=p, case_insensitive=TRUE)
will do the same,
except it uses fixed (i.e. literal) expression,
and it does not distinguish between upper case and lower case characters.
'tinycodet' adds some convenience functions based on
the stri_opts_
- functions in 'stringi':
s_regex(p, ...)
is equivalent to list(regex = p, ...)
s_fixed(p, ...)
is equivalent to list(fixed = p, ...)
s_coll(p, ...)
is equivalent to list(coll = p, ...)
s_chrcls(p, ...)
is equivalent to list(charclass = p, ... )
With the ellipsis (...
)
being passed to the appropriate
'stringi'-functions
when it matches their arguments.
'stringi' infix operators start with "%s
",
though they all have an alias starting with "%stri
".
In analogy to that, the above functions start with "s_
"
rather than "stri_
", as they are all meant for infix operators only.
s_regex(
p,
case_insensitive,
comments,
dotall,
multiline,
time_limit,
stack_limit,
...
)
s_fixed(p, case_insensitive, overlap, ...)
s_coll(
p,
locale,
strength,
alternate_shifted,
french,
uppercase_first,
case_level,
numeric,
normalization,
...
)
s_chrcls(p, ...)
p |
|
case_insensitive |
see stri_opts_regex and stri_opts_fixed. |
comments , dotall , multiline |
see stri_opts_regex. |
time_limit , stack_limit |
see stri_opts_regex. |
... |
additional arguments not part of the |
overlap |
see stri_opts_fixed. |
locale , strength , alternate_shifted |
see stri_opts_collator. |
french , normalization , numeric |
see stri_opts_collator. |
uppercase_first , case_level |
see stri_opts_collator. |
A list with arguments to be passed to the appropriate functions.
x <- c(paste0(letters[1:13], collapse=""), paste0(letters[14:26], collapse=""))
print(x)
p <- rep("a|e|i|o|u", 2) # same as p <- list(regex=rep("a|e|i|o|u", 2))
x %s/% p # count how often vowels appear in each string of vector x.
x <- c(paste0(letters[1:13], collapse=""), paste0(letters[14:26], collapse=""))
print(x)
x %s/% list(regex = rep("A|E|I|O|U", 2), case_insensitive = TRUE)
x %s/% s_regex(rep("A|E|I|O|U", 2), case_insensitive = TRUE)
x <- c(paste0(letters[1:13], collapse=""), paste0(letters[14:26], collapse=""))
print(x)
p <- list(fixed = c("A", "A"), case_insensitive=TRUE)
x %s{}% p
x %s!{}% p
p <- s_fixed(c("A", "A"), case_insensitive=TRUE)
x %s{}% p
x %s!{}% p