Add 'exclude' function for dropping variables in 'alter'

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: comprehenr
 Type: Package
 Title: List Comprehensions
-Version: 0.6.5
+Version: 0.6.6
 Maintainer: Gregory Demin <gdemin@gmail.com>
 Authors@R: person("Gregory", "Demin", email = "gdemin@gmail.com",
          role = c("aut", "cre"))

NAMESPACE

@@ -2,6 +2,7 @@
 
 export(alter)
 export(enumerate)
+export(exclude)
 export(lag_list)
 export(mark)
 export(numerate)

NEWS

@@ -1,3 +1,7 @@
+0.6.6 (07.06.2019)
+================
+* add 'exclude' function for dropping elements from data.frame/list in 'alter'
+
 0.6.5 (09.04.2019)
 ================
 * add 'alter' function for conditional lists/data.frames modification

R/to_list.R

@@ -4,10 +4,12 @@
 #' Expression should be started with \code{for} ,  \code{while} or
 #' \code{repeat}. You can iterate over multiple lists if you provide several
 #' loop variables in backticks. See examples.}
-#' \item{\code{to_vec}}{ is the same as \code{to_list} but return vector. See examples.}
+#' \item{\code{to_vec}}{ is the same as 'to_list' but return vector. See examples.}
 #' \item{\code{alter}}{ return the same type as its argument but with modified
 #' elements. It is useful for altering existing data.frames or lists. See
 #' examples.}
+#' \item{\code{exclude}}{ is an auxiliary function for dropping elements in
+#' 'alter'. There are no arguments for this function.}
 #' }
 #' @param expr expression which starts with \code{for} ,  \code{while} or \code{repeat}.
 #' @param recursive	logical. Should unlisting be applied to list components of result? See \link[base]{unlist} for details.
@@ -50,6 +52,10 @@
 #' res = alter(for(i in iris) if(is.factor(i)) as.character(i))
 #' str(res)
 #'
+#' # exclude factors from data.frame
+#' res = alter(for(i in iris) if(is.factor(i)) exclude())
+#' str(res)
+#'
 #' # 'data' argument example
 #' # specify which columns to map with a numeric vector of positions:
 #' res = alter(
@@ -164,16 +170,20 @@ add_assignment_to_loop = function(expr, result_exists = FALSE){
         expr[[last_item]] = bquote({
             .___curr = {.(expr[[last_item]])}
             .___counter = .___counter + 1
-            if(!is.null(.___curr)){
-                .___res[[.___counter]] = .___curr
+            if(inherits(.___curr, "exclude")){
+                .___res[[.___counter]] = NULL
+            } else {
+                if(!is.null(.___curr)){
+                    .___res[[.___counter]] = .___curr
+                }
             }
 
         })
     } else {
         expr[[last_item]] = bquote({
 
             .___curr = {.(expr[[last_item]])}
-            if(!is.null(.___curr)){
+            if(!is.null(.___curr) && !inherits(.___curr, "exclude")){
                 .___counter = .___counter + 1
                 .___res[[.___counter]] = .___curr
             }
@@ -201,3 +211,12 @@ alter = function(expr, data = NULL){
     res
 
 }
+
+
+#' @rdname to_list
+#' @export
+exclude = function(){
+    res = numeric(0)
+    class(res) = "exclude"
+    res
+}

README.md

@@ -58,6 +58,10 @@ str(res)
 res = alter(for(i in iris) if(is.factor(i)) as.character(i))
 str(res)
 
+# drop factors
+res = alter(for(i in iris) if(is.factor(i)) exclude())
+str(res)
+
 # 'data' argument example
 # specify which columns to map with a numeric vector of positions:
 res = alter(

tests/testthat/test_to_list.R

@@ -5,6 +5,11 @@ expect_identical(
     list(1L,3L,5L,7L,9L)
 )
 
+expect_identical(
+    to_list(for(i in 1:10) if(i %% 2 !=0) i else exclude()),
+    list(1L,3L,5L,7L,9L)
+)
+
 expect_identical(
     to_list(for(i in 1:10) if(i>1000) i),
     list()
@@ -126,6 +131,11 @@ res_iris = iris
 res_iris[,-5] = lapply(iris[,-5], scale)
 expect_equal(iris2, res_iris)
 
+data(iris)
+iris2 = alter(for(i in iris) if(is.factor(i)) exclude())
+res_iris = iris[,-5]
+expect_equal(iris2, res_iris)
+
 iris2 = alter(for(`name, value` in mark(iris)) if(endsWith(name, "Width")) scale(value), data = iris)
 
 res_iris = iris

vignettes/Introduction.R

@@ -40,6 +40,10 @@ str(res)
 res = alter(for(i in iris) if(is.factor(i)) as.character(i))
 str(res)
 
+# drop factors
+res = alter(for(i in iris) if(is.factor(i)) exclude())
+str(res)
+
 # 'data' argument example
 # specify which columns to map with a numeric vector of positions:
 res = alter(

vignettes/Introduction.html

@@ -289,6 +289,9 @@
 code > span.fu { color: #900; font-weight: bold; }  code > span.er { color: #a61717; background-color: #e3d2d2; } 
 </style>
 
+
+
+
 </head>
 
 <body>
@@ -385,44 +388,53 @@ <h1 class="title toc-ignore">List Comprehensions in R</h1>
 <a class="sourceLine" id="cb5-27" data-line-number="27"><span class="co">#&gt;  $ Petal.Width : num  0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...</span></a>
 <a class="sourceLine" id="cb5-28" data-line-number="28"><span class="co">#&gt;  $ Species     : chr  &quot;setosa&quot; &quot;setosa&quot; &quot;setosa&quot; &quot;setosa&quot; ...</span></a>
 <a class="sourceLine" id="cb5-29" data-line-number="29"></a>
-<a class="sourceLine" id="cb5-30" data-line-number="30"><span class="co"># 'data' argument example</span></a>
-<a class="sourceLine" id="cb5-31" data-line-number="31"><span class="co"># specify which columns to map with a numeric vector of positions:</span></a>
-<a class="sourceLine" id="cb5-32" data-line-number="32">res =<span class="st"> </span><span class="kw">alter</span>(</a>
-<a class="sourceLine" id="cb5-33" data-line-number="33">    <span class="cf">for</span>(<span class="st">`</span><span class="dt">i, value</span><span class="st">`</span> <span class="cf">in</span> <span class="kw">numerate</span>(mtcars)) <span class="cf">if</span>(i <span class="op">%in%</span><span class="st"> </span><span class="kw">c</span>(<span class="dv">1</span>, <span class="dv">4</span>, <span class="dv">5</span>)) <span class="kw">as.character</span>(value),</a>
-<a class="sourceLine" id="cb5-34" data-line-number="34">    <span class="dt">data =</span> mtcars</a>
-<a class="sourceLine" id="cb5-35" data-line-number="35">)</a>
-<a class="sourceLine" id="cb5-36" data-line-number="36"><span class="kw">str</span>(res)</a>
-<a class="sourceLine" id="cb5-37" data-line-number="37"><span class="co">#&gt; 'data.frame':    32 obs. of  11 variables:</span></a>
-<a class="sourceLine" id="cb5-38" data-line-number="38"><span class="co">#&gt;  $ mpg : chr  &quot;21&quot; &quot;21&quot; &quot;22.8&quot; &quot;21.4&quot; ...</span></a>
-<a class="sourceLine" id="cb5-39" data-line-number="39"><span class="co">#&gt;  $ cyl : num  6 6 4 6 8 6 8 4 4 6 ...</span></a>
-<a class="sourceLine" id="cb5-40" data-line-number="40"><span class="co">#&gt;  $ disp: num  160 160 108 258 360 ...</span></a>
-<a class="sourceLine" id="cb5-41" data-line-number="41"><span class="co">#&gt;  $ hp  : chr  &quot;110&quot; &quot;110&quot; &quot;93&quot; &quot;110&quot; ...</span></a>
-<a class="sourceLine" id="cb5-42" data-line-number="42"><span class="co">#&gt;  $ drat: chr  &quot;3.9&quot; &quot;3.9&quot; &quot;3.85&quot; &quot;3.08&quot; ...</span></a>
-<a class="sourceLine" id="cb5-43" data-line-number="43"><span class="co">#&gt;  $ wt  : num  2.62 2.88 2.32 3.21 3.44 ...</span></a>
-<a class="sourceLine" id="cb5-44" data-line-number="44"><span class="co">#&gt;  $ qsec: num  16.5 17 18.6 19.4 17 ...</span></a>
-<a class="sourceLine" id="cb5-45" data-line-number="45"><span class="co">#&gt;  $ vs  : num  0 0 1 1 0 1 0 1 1 1 ...</span></a>
-<a class="sourceLine" id="cb5-46" data-line-number="46"><span class="co">#&gt;  $ am  : num  1 1 1 0 0 0 0 0 0 0 ...</span></a>
-<a class="sourceLine" id="cb5-47" data-line-number="47"><span class="co">#&gt;  $ gear: num  4 4 4 3 3 3 3 4 4 4 ...</span></a>
-<a class="sourceLine" id="cb5-48" data-line-number="48"><span class="co">#&gt;  $ carb: num  4 4 1 1 2 1 4 2 2 4 ...</span></a>
-<a class="sourceLine" id="cb5-49" data-line-number="49"></a>
-<a class="sourceLine" id="cb5-50" data-line-number="50"><span class="co"># or with a vector of names:</span></a>
-<a class="sourceLine" id="cb5-51" data-line-number="51">res =<span class="st"> </span><span class="kw">alter</span>(</a>
-<a class="sourceLine" id="cb5-52" data-line-number="52">    <span class="cf">for</span>(<span class="st">`</span><span class="dt">name, value</span><span class="st">`</span> <span class="cf">in</span> <span class="kw">mark</span>(mtcars)) <span class="cf">if</span>(name <span class="op">%in%</span><span class="st"> </span><span class="kw">c</span>(<span class="st">&quot;cyl&quot;</span>, <span class="st">&quot;am&quot;</span>)) <span class="kw">as.character</span>(value),</a>
-<a class="sourceLine" id="cb5-53" data-line-number="53">    <span class="dt">data =</span> mtcars</a>
-<a class="sourceLine" id="cb5-54" data-line-number="54">)</a>
-<a class="sourceLine" id="cb5-55" data-line-number="55"><span class="kw">str</span>(res)</a>
-<a class="sourceLine" id="cb5-56" data-line-number="56"><span class="co">#&gt; 'data.frame':    32 obs. of  11 variables:</span></a>
-<a class="sourceLine" id="cb5-57" data-line-number="57"><span class="co">#&gt;  $ mpg : num  21 21 22.8 21.4 18.7 18.1 14.3 24.4 22.8 19.2 ...</span></a>
-<a class="sourceLine" id="cb5-58" data-line-number="58"><span class="co">#&gt;  $ cyl : chr  &quot;6&quot; &quot;6&quot; &quot;4&quot; &quot;6&quot; ...</span></a>
-<a class="sourceLine" id="cb5-59" data-line-number="59"><span class="co">#&gt;  $ disp: num  160 160 108 258 360 ...</span></a>
-<a class="sourceLine" id="cb5-60" data-line-number="60"><span class="co">#&gt;  $ hp  : num  110 110 93 110 175 105 245 62 95 123 ...</span></a>
-<a class="sourceLine" id="cb5-61" data-line-number="61"><span class="co">#&gt;  $ drat: num  3.9 3.9 3.85 3.08 3.15 2.76 3.21 3.69 3.92 3.92 ...</span></a>
-<a class="sourceLine" id="cb5-62" data-line-number="62"><span class="co">#&gt;  $ wt  : num  2.62 2.88 2.32 3.21 3.44 ...</span></a>
-<a class="sourceLine" id="cb5-63" data-line-number="63"><span class="co">#&gt;  $ qsec: num  16.5 17 18.6 19.4 17 ...</span></a>
-<a class="sourceLine" id="cb5-64" data-line-number="64"><span class="co">#&gt;  $ vs  : num  0 0 1 1 0 1 0 1 1 1 ...</span></a>
-<a class="sourceLine" id="cb5-65" data-line-number="65"><span class="co">#&gt;  $ am  : chr  &quot;1&quot; &quot;1&quot; &quot;1&quot; &quot;0&quot; ...</span></a>
-<a class="sourceLine" id="cb5-66" data-line-number="66"><span class="co">#&gt;  $ gear: num  4 4 4 3 3 3 3 4 4 4 ...</span></a>
-<a class="sourceLine" id="cb5-67" data-line-number="67"><span class="co">#&gt;  $ carb: num  4 4 1 1 2 1 4 2 2 4 ...</span></a></code></pre></div>
+<a class="sourceLine" id="cb5-30" data-line-number="30"><span class="co"># drop factors</span></a>
+<a class="sourceLine" id="cb5-31" data-line-number="31">res =<span class="st"> </span><span class="kw">alter</span>(<span class="cf">for</span>(i <span class="cf">in</span> iris) <span class="cf">if</span>(<span class="kw">is.factor</span>(i)) <span class="kw">exclude</span>())</a>
+<a class="sourceLine" id="cb5-32" data-line-number="32"><span class="kw">str</span>(res)</a>
+<a class="sourceLine" id="cb5-33" data-line-number="33"><span class="co">#&gt; 'data.frame':    150 obs. of  4 variables:</span></a>
+<a class="sourceLine" id="cb5-34" data-line-number="34"><span class="co">#&gt;  $ Sepal.Length: num  5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...</span></a>
+<a class="sourceLine" id="cb5-35" data-line-number="35"><span class="co">#&gt;  $ Sepal.Width : num  3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...</span></a>
+<a class="sourceLine" id="cb5-36" data-line-number="36"><span class="co">#&gt;  $ Petal.Length: num  1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...</span></a>
+<a class="sourceLine" id="cb5-37" data-line-number="37"><span class="co">#&gt;  $ Petal.Width : num  0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...</span></a>
+<a class="sourceLine" id="cb5-38" data-line-number="38"></a>
+<a class="sourceLine" id="cb5-39" data-line-number="39"><span class="co"># 'data' argument example</span></a>
+<a class="sourceLine" id="cb5-40" data-line-number="40"><span class="co"># specify which columns to map with a numeric vector of positions:</span></a>
+<a class="sourceLine" id="cb5-41" data-line-number="41">res =<span class="st"> </span><span class="kw">alter</span>(</a>
+<a class="sourceLine" id="cb5-42" data-line-number="42">    <span class="cf">for</span>(<span class="st">`</span><span class="dt">i, value</span><span class="st">`</span> <span class="cf">in</span> <span class="kw">numerate</span>(mtcars)) <span class="cf">if</span>(i <span class="op">%in%</span><span class="st"> </span><span class="kw">c</span>(<span class="dv">1</span>, <span class="dv">4</span>, <span class="dv">5</span>)) <span class="kw">as.character</span>(value),</a>
+<a class="sourceLine" id="cb5-43" data-line-number="43">    <span class="dt">data =</span> mtcars</a>
+<a class="sourceLine" id="cb5-44" data-line-number="44">)</a>
+<a class="sourceLine" id="cb5-45" data-line-number="45"><span class="kw">str</span>(res)</a>
+<a class="sourceLine" id="cb5-46" data-line-number="46"><span class="co">#&gt; 'data.frame':    32 obs. of  11 variables:</span></a>
+<a class="sourceLine" id="cb5-47" data-line-number="47"><span class="co">#&gt;  $ mpg : chr  &quot;21&quot; &quot;21&quot; &quot;22.8&quot; &quot;21.4&quot; ...</span></a>
+<a class="sourceLine" id="cb5-48" data-line-number="48"><span class="co">#&gt;  $ cyl : num  6 6 4 6 8 6 8 4 4 6 ...</span></a>
+<a class="sourceLine" id="cb5-49" data-line-number="49"><span class="co">#&gt;  $ disp: num  160 160 108 258 360 ...</span></a>
+<a class="sourceLine" id="cb5-50" data-line-number="50"><span class="co">#&gt;  $ hp  : chr  &quot;110&quot; &quot;110&quot; &quot;93&quot; &quot;110&quot; ...</span></a>
+<a class="sourceLine" id="cb5-51" data-line-number="51"><span class="co">#&gt;  $ drat: chr  &quot;3.9&quot; &quot;3.9&quot; &quot;3.85&quot; &quot;3.08&quot; ...</span></a>
+<a class="sourceLine" id="cb5-52" data-line-number="52"><span class="co">#&gt;  $ wt  : num  2.62 2.88 2.32 3.21 3.44 ...</span></a>
+<a class="sourceLine" id="cb5-53" data-line-number="53"><span class="co">#&gt;  $ qsec: num  16.5 17 18.6 19.4 17 ...</span></a>
+<a class="sourceLine" id="cb5-54" data-line-number="54"><span class="co">#&gt;  $ vs  : num  0 0 1 1 0 1 0 1 1 1 ...</span></a>
+<a class="sourceLine" id="cb5-55" data-line-number="55"><span class="co">#&gt;  $ am  : num  1 1 1 0 0 0 0 0 0 0 ...</span></a>
+<a class="sourceLine" id="cb5-56" data-line-number="56"><span class="co">#&gt;  $ gear: num  4 4 4 3 3 3 3 4 4 4 ...</span></a>
+<a class="sourceLine" id="cb5-57" data-line-number="57"><span class="co">#&gt;  $ carb: num  4 4 1 1 2 1 4 2 2 4 ...</span></a>
+<a class="sourceLine" id="cb5-58" data-line-number="58"></a>
+<a class="sourceLine" id="cb5-59" data-line-number="59"><span class="co"># or with a vector of names:</span></a>
+<a class="sourceLine" id="cb5-60" data-line-number="60">res =<span class="st"> </span><span class="kw">alter</span>(</a>
+<a class="sourceLine" id="cb5-61" data-line-number="61">    <span class="cf">for</span>(<span class="st">`</span><span class="dt">name, value</span><span class="st">`</span> <span class="cf">in</span> <span class="kw">mark</span>(mtcars)) <span class="cf">if</span>(name <span class="op">%in%</span><span class="st"> </span><span class="kw">c</span>(<span class="st">&quot;cyl&quot;</span>, <span class="st">&quot;am&quot;</span>)) <span class="kw">as.character</span>(value),</a>
+<a class="sourceLine" id="cb5-62" data-line-number="62">    <span class="dt">data =</span> mtcars</a>
+<a class="sourceLine" id="cb5-63" data-line-number="63">)</a>
+<a class="sourceLine" id="cb5-64" data-line-number="64"><span class="kw">str</span>(res)</a>
+<a class="sourceLine" id="cb5-65" data-line-number="65"><span class="co">#&gt; 'data.frame':    32 obs. of  11 variables:</span></a>
+<a class="sourceLine" id="cb5-66" data-line-number="66"><span class="co">#&gt;  $ mpg : num  21 21 22.8 21.4 18.7 18.1 14.3 24.4 22.8 19.2 ...</span></a>
+<a class="sourceLine" id="cb5-67" data-line-number="67"><span class="co">#&gt;  $ cyl : chr  &quot;6&quot; &quot;6&quot; &quot;4&quot; &quot;6&quot; ...</span></a>
+<a class="sourceLine" id="cb5-68" data-line-number="68"><span class="co">#&gt;  $ disp: num  160 160 108 258 360 ...</span></a>
+<a class="sourceLine" id="cb5-69" data-line-number="69"><span class="co">#&gt;  $ hp  : num  110 110 93 110 175 105 245 62 95 123 ...</span></a>
+<a class="sourceLine" id="cb5-70" data-line-number="70"><span class="co">#&gt;  $ drat: num  3.9 3.9 3.85 3.08 3.15 2.76 3.21 3.69 3.92 3.92 ...</span></a>
+<a class="sourceLine" id="cb5-71" data-line-number="71"><span class="co">#&gt;  $ wt  : num  2.62 2.88 2.32 3.21 3.44 ...</span></a>
+<a class="sourceLine" id="cb5-72" data-line-number="72"><span class="co">#&gt;  $ qsec: num  16.5 17 18.6 19.4 17 ...</span></a>
+<a class="sourceLine" id="cb5-73" data-line-number="73"><span class="co">#&gt;  $ vs  : num  0 0 1 1 0 1 0 1 1 1 ...</span></a>
+<a class="sourceLine" id="cb5-74" data-line-number="74"><span class="co">#&gt;  $ am  : chr  &quot;1&quot; &quot;1&quot; &quot;1&quot; &quot;0&quot; ...</span></a>
+<a class="sourceLine" id="cb5-75" data-line-number="75"><span class="co">#&gt;  $ gear: num  4 4 4 3 3 3 3 4 4 4 ...</span></a>
+<a class="sourceLine" id="cb5-76" data-line-number="76"><span class="co">#&gt;  $ carb: num  4 4 1 1 2 1 4 2 2 4 ...</span></a></code></pre></div>
 
 
 

vignettes/Introduction.rmd

@@ -68,6 +68,10 @@ str(res)
 res = alter(for(i in iris) if(is.factor(i)) as.character(i))
 str(res)
 
+# drop factors
+res = alter(for(i in iris) if(is.factor(i)) exclude())
+str(res)
+
 # 'data' argument example
 # specify which columns to map with a numeric vector of positions:
 res = alter(