# Utility operators Succinct or convenience operators ```r a %&% b x %**% y a %!in% b vector %except% condition x %grepling% patt x %is.not.a% what x %is.a% what x %is.not.an% what x %is.an% what x %matching% patt a %not.in% b a %not.in.range% b x %perling% patt x %that.match% patt x %that.dont.match% patt a %that.are.in% b x %without.name% what a %in.range% b a %such.that% b a %SUCH.THAT% b from %upto% to from %downto% to x %where% cond x %where.warn% cond a %<-% value # really e.g. {x;y} %<-% list( 'yes', sqrt(pi)) to create x & y ``` ## Arguments - `a, b, vector, condition, x, y, what, patt, from, to, cond, value`: see Arguments by function . ## Returns - **%&%**: character vector. If either is zero-length, so is the result (unlike `paste`). - **%**%**: numeric, possibly a matrix - **%upto%, %downto%**: numeric - **%is.a%, %in%, etc**: logical - **%<-%**: technically NULL return, but it overwrites / creates objects; see below... - **All others**: same type as first argument. ## Arguments by function `%&%` a, b: character vectors to be `paste`d with no separator. If either is zero-length, so is the result (unlike `paste`). `%**%` x, y: matrices or vectors to be multiplied using `%*%` but with less fuss about dimensions `%!in%`, `%that.are.in%` a, b: vectors (character, numeric, complex, or logical). `%except%` vector, condition: character or numeric vectors `%in.range%`, `%not.in.range%` a, b: numeric vectors. `%is.a%`, etc. x: object whose class is to be checked `%is.a%`, etc. what: class name `%matching%`, `%that.match%`, `%that.dont.match%`, `%grepling%`, `%perling%` x: character vector `%matching%`, `%that.match%`, `%that.dont.match%`, `%grepling%`, `%perling%` patt: character vector of regexps, with perl syntax for `%perling%` `%such.that%`, `%SUCH.THAT%` a: vector `%such.that%`, `%SUCH.THAT%` b: expression containing a `.`, to subscript `a` with `%upto%`, `%downto%` from, to: numeric(1) `%where%`, `%where.warn%` x: data.frame `%where%`, `%where.warn%` cond: unquoted expression to be `eval`ed in context of `x`, then in the calling frame of `%where%` (or `.GlobalEnv`). Should evaluate to logical (or maybe numeric or character); NA is treated as FALSE. Wrap `cond` in parentheses to avoid trouble with operator precedence. `%without.name%` x: object with `names` attribute `%without.name%` what: character vector of names to drop `%<-%` a, value: `value` should be a list, and `a` should be e.g. `{x;y;z}` with as many elements as `value` has. The elements of `value` are assigned, in order, to the objects named in `a`, which are created / overwritten in the calling environment. ## Author(s) Mark Bravington ## See Also bquote ## Examples ```r "a" %&% "b" # "ab" matrix( 1:4, 2, 2) %**% matrix( 1:2, 2, 1) # c( 7, 10); '%*%' gives matrix result matrix( 1:2, 2, 1) %**% matrix( 1:4, 2, 2) # c( 5, 11); '%*%' gives error 1:2 %**% matrix( 1:4, 2, 2) # '%*%' gives matrix result 1:5 %!in% 3:4 # c( TRUE, TRUE, FALSE, FALSE, TRUE) 1:5 %not.in% 3:4 # c( TRUE, TRUE, FALSE, FALSE, TRUE) 1:5 %that.are.in% 3:4 # c( 3, 4) trf <- try( 1+"nonsense") if( trf %is.not.a% "try-error") cat( "OK\n") else cat( "not OK\n") 1:5 %except% c(2,4,6) # c(1,3,5) c( alpha=1, beta=2) %without.name% "alpha" # c( beta=2) 1:5 %in.range% c( 2, 4) # c(F,T,T,T,F) 1:5 %not.in.range% c( 2, 4) # c(T,F,F,F,T) c( "cat", "hat", "dog", "brick") %matching% c( "at", "ic") # cat hat brick c( "cat", "hat", "dog", "brick") %that.match% c( "at", "ic") # cat hat brick; ... # ... synonym for '%matching%' c( "cat", "hat", "dog", "brick") %that.dont.match% c( "at", "ic") # dog; ... # ... like '%except%' but for regexps 1 %upto% 2 # 1:2 1 %upto% 0 # numeric( 0); use %upto% rather than : in for-loops to avoid unintended errors 1 %downto% 0 # 1:0 1 %downto% 2 # numeric( 0) ff <- function( which.row) { x <- data.frame( a=1:3, b=4:6) x %where% (a==which.row) } ff( 2) # data.frame( a=2, b=5) x <- data.frame( start=1:3, end=c( 4, 5, 0)) x %where.warn% (start < end) # gives warning about row 3 (1:5) %such.that% (.>2) # 3,4,5 listio <- list( a=1, b=2) chars <- cq( a, b) chars %SUCH.THAT% (listio[[.]]==2) # 'b'; %such.that% won't work because [[]] can't handle xtuples {x;y} %<-% list( 'yes', sqrt(pi)) # x: [1] "yes" # y: [1] 1.772 ```

mvbutils.operators function