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DataFrame and methods

Description

This is a 'data.table' like implementation of a data.frame. Either dplyr ordata.table is used as backend. The only purpose is to haveR CMD checkfriendly syntax.

Usage

DataFrame(...)as.DataFrame(x, ...)## Default S3 method:as.DataFrame(x, ...)## S3 method for class 'data.frame'as.DataFrame(x, ...)## S3 method for class 'DataFrame'x[i, j, ..., by, sby, drop]

Arguments

Details

OneSidedFormula is always used for subsetting rows.

TwoSidedFormula is used instead of name-value expressions insummarise andmutate.

See Also

mutar,FL

Examples

data("airquality")dat <- as.DataFrame(airquality)dat[~ Month > 4, ][meanWind ~ mean(Wind), sby = "Month"]["meanWind"]dat[FL(.n ~ mean(.n), .n = c("Wind", "Temp")), sby = "Month"]

Dynamically generate formulas

Description

Function to dynamically generate formulas - (F)ormula (L)ist - to be used inmutar.

Usage

FL(..., .n = NULL, pattern = "\\.n")makeFormulas(..., .n, pattern = "\\.n")## S3 method for class 'FormulaList'update(object, data, ...)

Arguments

See Also

mutar

Examples

FL(.n ~ mean(.n), .n = "variable")as(makeFormulas(.n ~ mean(.n), .n = "variable"), "FormulaList")

Coerce a formula into a function

Description

Convert a formula into a function. Seemap andextract forexamples.

Usage

## S3 method for class 'formula'as.function(x, ...)

Arguments

Value

An object inheriting from class function.

Examples

as.function(~ .)(1)as.function(x ~ x)(1)as.function(f(x, y) ~ c(x, y))(1, 2)as.function(numeric : x ~ x)(1) # check for classas.function(numeric(1) : x ~ x)(1) # check for class + length

Bind rows

Description

This is a wrapper aroundrbindlist to preserve the inputclass.

Usage

bindRows(x, id = NULL, useNames = TRUE, fill = TRUE)

Arguments

Value

If the first element ofx inherits fromdata.frame the typethat first element.

x else.

Extract elements from a vector

Description

Extract elements from an object as S4 generic function. See the examples.

Usage

extract(x, ind, ...)## S4 method for signature 'list,'function''extract(x, ind, ...)## S4 method for signature 'atomic,'function''extract(x, ind, ...)## S4 method for signature 'ANY,formula'extract(x, ind, ...)## S4 method for signature 'atomicORlist,numericORintegerORlogical'extract(x, ind, ...)## S4 method for signature 'ANY,character'extract(x, ind, ...)## S4 method for signature 'data.frame,character'extract(x, ind, ...)extract2(x, ind, ...)## S4 method for signature 'atomicORlist,numericORinteger'extract2(x, ind, ...)## S4 method for signature 'ANY,formula'extract2(x, ind, ...)## S4 method for signature 'atomicORlist,'function''extract2(x, ind, ...)## S4 method for signature 'ANY,character'extract2(x, ind, ...)

Arguments

Examples

extract(1:15, ~ 15 %% . == 0)extract(list(xy = 1, zy = 2), "^z")extract(list(x = 1, z = 2), 1)extract(list(x = 1, y = ""), is.character)# Example: even numbers:is.even <- function(x) (x %% 2) == 0sum((1:10)[is.even(1:10)])extract(1:10, ~ . %% 2 == 0) %>% sumextract(1:10, is.even) %>% sum# Example: factors of 15extract(1:15, ~ 15 %% . == 0)# Example: relative prime numbersgcd <- function(a, b) {  .gcd <- function(a, b) if (b == 0) a else Recall(b, a %% b)  flatmap(a ~ b, .gcd)}extract(1:10, x ~ gcd(x, 10) == 1)# Example: real prime numbersisPrime <- function(n) {  .isPrime <- function(n) {    iter <- function(i) {      if (i * i > n) TRUE      else if (n %% i == 0 || n %% (i + 2) == 0) FALSE      else Recall(i + 6)    }    if (n <= 1) FALSE    else if (n <= 3) TRUE    else if (n %% 2 == 0 || n %% 3 == 0) FALSE    else iter(5)  }  flatmap(n, x ~ .isPrime(x))}extract(1:10, isPrime)

An implementation of map

Description

An implementation of map and flatmap. They support the use of formulas assyntactic sugar for anonymous functions.

Usage

map(x, f, ...)## S4 method for signature 'ANY,formula'map(x, f, ...)## S4 method for signature 'atomic,'function''map(x, f, ...)## S4 method for signature 'list,'function''map(x, f, p = function(x) TRUE, ...)## S4 method for signature 'list,numericORcharacteORlogical'map(x, f, ...)## S4 method for signature 'MList,'function''map(x, f, ..., simplify = FALSE)## S4 method for signature 'formula,'function''map(x, f, ...)flatmap(x, f, ..., flatten = unlist)## S4 method for signature 'ANY,formula'flatmap(x, f, ..., flatten = unlist)sac(x, f, by, ..., combine = bindRows)## S4 method for signature 'data.frame,'function''sac(x, f, by, ..., combine = bindRows)## S4 method for signature 'ANY,formula'sac(x, f, by, ..., combine = bindRows)vmap(x, f, ..., .mc = min(length(x), detectCores()), .bar = "bar")

Arguments

Details

map will dispatch tolapply. Whenx is aformula this is interpreted as a multivariate map; this is implementedusingmapply. Whenx is a data.framemap will iterateover columns, however the return value is adata.frame.p canbe used to map over a subset ofx.

flatmap will dispatch tomap. The result is then wrapped byflatten which isunlist by default.

sac is a naive implementation of split-apply-combine and implementedusingflatmap.

vmap is a 'verbose' version ofmap and provides a progress barand a link to parallel map (mclapply).

map,flatmap, andsac can be extended; they are S4generic functions. You don't and should not implement a new method forformulas. This method will coerce a formula into a function and pass it downto your map(newtype, function) method.

Examples

# Sugar for anonymous functionsmap(data.frame(y = 1:10, z = 2), x ~ x + 1)map(data.frame(y = 1:10, z = 2), x ~ x + 1, is.numeric)map(data.frame(y = 1:10, z = 2), x ~ x + 1, x ~ all(x == 2))sac(data.frame(y = 1:10, z = 1:2), df ~ data.frame(my = mean(df$y)), "z")# Trigger a multivariate map with a formulamap(1:2 ~ 3:4, f(x, y) ~ x + y)map(1:2 ~ 3:4, f(x, y) ~ x + y, simplify = TRUE)map(1:2 ~ 3:4, f(x, y, z) ~ x + y + z, z = 1)# Extracting values from listsmap(list(1:2, 3:4), 2)map(list(1:3, 2:5), 2:3)map(list(1:3, 2:5), c(TRUE, FALSE, TRUE))# Some type checking along the waymap(as.numeric(1:2), numeric : x ~ x)map(1:2, integer(1) : x ~ x)map(1:2, numeric(1) : x ~ x + 0.5)

Tools for Data Frames

Description

mutar is literally the same function as[.DataFrame and can beused as interface to dplyr or data.table. Other functions here listed are aconvenience to mimic dplyr's syntax in aR CMD check friendly way.These functions can also be used with S4 data.frame(s) / data_frame(s) /data.table(s). They will always try to preserve the input class.

Usage

mutar(x, i, j, ..., by, sby, drop)filtar(x, i)sumar(x, ..., by)withReference(expr)

Arguments

Details

The real workhorse of this interface ismutar. All other functionsexist to ease the transition from dplyr.

OneSidedFormula is always used for subsetting rows.

TwoSidedFormula is used instead of name-value expressions. Instead ofwritingx = 1 you simply writex ~ 1.

FormulaList can be used to repeat the same operation on differentcolumns. See more details inFL.

See Also

extract,DataFrame,FL

Examples

data("airquality")airquality %>%  filtar(~Month > 4) %>%  mutar(meanWind ~ mean(Wind), by = "Month") %>%  sumar(meanWind ~ mean(Wind), by = "Month") %>%  extract("meanWind")airquality %>%  sumar(    .n ~ mean(.n) | c("Wind", "Temp"),    by = "Month"  )# Enable data.tables reference semantics with:withReference({  x <- data.table::data.table(x = 1)  mutar(x, y ~ 2)})## Not run: # Use dplyr as back-end:options(dat.use.dplyr = TRUE)x <- data.frame(x = 1)mutar(x, y ~ dplyr::n())## End(Not run)

Objects exported from other packages

Description

These objects are imported from other packages. Follow the linksbelow to see their documentation.

magrittr

%>%

Replace elements in a vector

Description

This function replaces elements in a vector. It is a link toreplace as a generic function.

Usage

replace(x, ind, values, ...)## S4 method for signature 'ANY,'function''replace(x, ind, values, ...)## S4 method for signature 'ANY,formula'replace(x, ind, values, ...)## S4 method for signature 'ANY,character'replace(x, ind, values, ...)

Arguments

Details

The idea is to provide a more flexible interface for thespecification of the index. It can be a character, numeric, integer orlogical which is then simply used inbase::replace. It can be aregular expression in which casex should be named – a character oflength 1 and a leading "^" is interpreted as regex. Whenind is afunction (or formula) andx is a list then it should be a predicatefunction – see the examples. When x is an atomic the function is appliedon x and the result is used for subsetting.

Examples

replace(c(1, 2, NA), is.na, 0)replace(c(1, 2, NA), rep(TRUE, 3), 0)replace(c(1, 2, NA), 3, 0)replace(list(x = 1, y = 2), "x", 0)replace(list(x = 1, y = 2), "^x$", 0)replace(list(x = 1, y = "a"), is.character, NULL)

Verbose apply function

Description

This apply function has a progress bar and enables computations inparallel. By default it is not verbose. As an interactive version with proper'verbose' output by default please usevmap.

Usage

verboseApply(x, f, ..., .mc = 1, .mapper = mclapply, .bar = "none")

Arguments

Examples

## Not run: verboseApply(  1:4,  function(...) Sys.sleep(1),  .bar = "bar",  .mc = 2 )## End(Not run)