comparison.cloud

0th

Percentile

Plot a comparison cloud

Plot a cloud comparing the frequencies of words across documents.

Usage
comparison.cloud(term.matrix,scale=c(4,.5),max.words=300, random.order=FALSE,rot.per=.1, colors=brewer.pal(ncol(term.matrix),"Dark2"), use.r.layout=FALSE,title.size=3,...)
Arguments
term.matrix
A term frequency matrix whose rows represent words and whose columns represent documents.
scale
A vector of length 2 indicating the range of the size of the words.
max.words
Maximum number of words to be plotted. least frequent terms dropped
random.order
plot words in random order. If false, they will be plotted in decreasing frequency
rot.per
proportion words with 90 degree rotation
colors
color words from least to most frequent
use.r.layout
if false, then c++ code is used for collision detection, otherwise R is used
title.size
Size of document titles
...
Additional parameters to be passed to text (and strheight,strwidth).
Details

Let $p_{i,j}$ be the rate at which word i occurs in document j, and $p_j$ be the average across documents($\sum_ip_{i,j}/ndocs$). The size of each word is mapped to its maximum deviation ( $max_i(p_{i,j}-p_j)$ ), and its angular position is determined by the document where that maximum occurs.

Value

nothing

Aliases
  • comparison.cloud
Examples

if(require(tm)){
	data(SOTU)
	corp <- SOTU
	corp <- tm_map(corp, removePunctuation)
	corp <- tm_map(corp, content_transformer(tolower))
	corp <- tm_map(corp, removeNumbers)
	corp <- tm_map(corp, function(x)removeWords(x,stopwords()))

	term.matrix <- TermDocumentMatrix(corp)
	term.matrix <- as.matrix(term.matrix)
	colnames(term.matrix) <- c("SOTU 2010","SOTU 2011")
	comparison.cloud(term.matrix,max.words=40,random.order=FALSE)
	commonality.cloud(term.matrix,max.words=40,random.order=FALSE)
}

Documentation reproduced from package wordcloud, version 2.5, License: LGPL-2.1

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