added safe option in qdap::multigsub as implemented by mgsub::mgsub

DESCRIPTION

@@ -11,7 +11,7 @@ Depends: R (>= 3.1.0), qdapDictionaries (>= 1.0.2), qdapRegex (>= 0.1.2), qdapTo
 Imports: chron, dplyr (>= 0.3), gdata, gender (>= 0.5.1), ggplot2 (>= 2.1.0), grid, gridExtra,
           igraph, methods, NLP, openNLP (>= 0.2-1), parallel, plotrix, RCurl, reports,
           reshape2, scales, stringdist, tidyr, tm (>= 0.7.2), tools, venneuler, wordcloud,
-          xlsx, XML
+          xlsx, XML, mgsub
 Suggests: koRpus, knitr, lda, proxy, stringi, SnowballC, testthat
 LazyData: TRUE
 VignetteBuilder: knitr

R/multigsub.R

@@ -19,6 +19,10 @@
 #' \code{pattern} string is sorted by number of characters to prevent substrings 
 #' replacing meta strings (e.g., \code{pattern = c("the", "then")} resorts to 
 #' search for "then" first).
+#' @param simultaneous logical. If \code{TRUE} then a slower method is used which 
+#' guarantees no conflicts in simulataneous string substitution (e.g., pattern =
+#' c("hey", "ho"), replacement = c("ho", "hey"), text.var = "hey ho, let's go!"
+#' will return "ho hey, let's go!").
 #' @param \dots Additional arguments passed to \code{\link[base]{gsub}}.
 #' @rdname multigsub
 #' @return \code{multigsub} - Returns a vector with the pattern replaced.
@@ -33,6 +37,7 @@
 #' multigsub(c("it's", "I'm"), c("it is", "I am"), DATA$state)
 #' mgsub(c("it's", "I'm"), c("it is", "I am"), DATA$state)
 #' mgsub("[[:punct:]]", "PUNC", DATA$state, fixed = FALSE)
+#' mgsub("hey ho, let's go!", c("hey", "ho"), c("ho", "hey"), simultaneous = TRUE)
 #'
 #' ## ====================== 
 #' ## `sub_holder` Function
@@ -54,7 +59,7 @@
 multigsub <-
 function (pattern, replacement, text.var, leadspace = FALSE, 
     trailspace = FALSE, fixed = TRUE, trim = TRUE, order.pattern = fixed, 
-    ...) {
+    simultaneous = FALSE, ...) {
 
     if (leadspace | trailspace) replacement <- spaste(replacement, trailing = trailspace, leading = leadspace)
 
@@ -64,9 +69,13 @@ function (pattern, replacement, text.var, leadspace = FALSE,
         if (length(replacement) != 1) replacement <- replacement[ord]
     }
     if (length(replacement) == 1) replacement <- rep(replacement, length(pattern))
-
-    for (i in seq_along(pattern)){
+
+    if (simultaneous) {
+      mgsub::mgsub(text.var, pattern, replacement, fixed = fixed, ...)
+    } else {
+      for (i in seq_along(pattern)){
         text.var <- gsub(pattern[i], replacement[i], text.var, fixed = fixed, ...)
+      }
     }
 
     if (trim) text.var <- gsub("\\s+", " ", gsub("^\\s+|\\s+$", "", text.var, perl=TRUE), perl=TRUE)

inst/Rmd_vignette/qdap_vignette.Rmd

@@ -1045,7 +1045,9 @@ trans_cloud(text, c("greg", "bob"), target.words=list(obs), caps.list=obs,
 
 <h4 id="mgsub">Multiple gsub</h4>
 
-The researcher may have the need to make multiple substitutions in a text.  An example of when this is needed is when a transcript is marked up with transcription coding convention specific to a particular transcription method.  These codes, while useful in some contexts, may lead to inaccurate word statistics.  The base R function `r HR2("http://stat.ethz.ch/R-manual/R-devel/library/base/html/grep.html", "gsub")` makes a single replacement of these types of coding conventions. The `r FUN("multigsub")` (alias `r FUN("mgsub")`) takes a vector of patterns to search for as well as a vector of replacements.  Note that the replacements occur sequentially rather than all at once. This means a previous (first in pattern string) sub could alter or be altered by a later sub.  `r FUN("mgsub")` is useful throughout multiple stages of the research process.
+The researcher may have the need to make multiple substitutions in a text.  An example of when this is needed is when a transcript is marked up with transcription coding convention specific to a particular transcription method.  These codes, while useful in some contexts, may lead to inaccurate word statistics.  The base R function `r HR2("http://stat.ethz.ch/R-manual/R-devel/library/base/html/grep.html", "gsub")` makes a single replacement of these types of coding conventions. The `r FUN("multigsub")` (alias `r FUN("mgsub")`) takes a vector of patterns to search for as well as a vector of replacements.  Note that the replacements occur sequentially rather than all at once (unless the simultaneous flag is set to `r TRUE`). This means a previous (first in pattern string) sub could alter or be altered by a later sub.  `r FUN("mgsub")` is useful throughout multiple stages of the research process.
+
+When the simultaneous flag is set, replacements occur simultaneously. This results in slower processing, but ensures the integrity of the substitutions.
 
 `r FT(orange, 5, text="&diams;")` **Multiple Substitutions**`r FT(orange, 5, text="&diams;")`
 ```{r}
@@ -1056,6 +1058,7 @@ mgsub(c("it's", "I'm"), "SINGLE REPLACEMENT", DATA$state)
 mgsub("[[:punct:]]", "PUNC", DATA$state, fixed = FALSE)
 ## Iterative "I'm" converts to "I am" which converts to "INTERATIVE"
 mgsub(c("it's", "I'm", "I am"), c("it is", "I am", "ITERATIVE"), DATA$state)
+mgsub("hey ho, let's go!", c("hey", "ho"), c("ho", "hey"), simultaneous = TRUE)
 ```