可以说我有以下内容：
x10 = data.frame(id = c(1,2,3),vars =c('top','down','top'),
text1=c('this is text','so is this','and this is too.'),
text2=c('we have more text here','and here too','and look at this, more text.'))
我想使用以下方法在Quanteda中创建一个dfm /语料库：
x1 = corpus(x10,docid_field='id',text_field=c(3:4),tolower=T)
显然，由于text_field只占用一列，因此会出错。除了建立两个语料库之外，还有其他更好的方法来解决这个问题吗？我可以建立2然后合并到id上吗？那是东西吗？
最佳答案
首先，让我们在不考虑字符值的情况下重新创建data.frame：
x10 = data.frame(id = c(1,2,3), vars = c('top','down','top'),
text1 = c('this is text', 'so is this', 'and this is too.'),
text2 = c('we have more text here', 'and here too', 'and look at this, more text.'),
stringsAsFactors = FALSE)
然后我们有两个选择。
方法1：重塑为“长”格式并创建单个语料库
首先“融合”数据，以便只有一个列，然后作为语料库导入。 （另一种方法是
tidy::gather()。）x10b <- reshape2::melt(x10, id.vars = c("id", "vars"),
measure.vars = c("text1", "text2"),
variable.name = "doc_id", value.name = "text")
# because corpus() takes document names from row names, by default
row.names(x10b) <- paste(x10b$doc_id, x10b$id, sep = "_")
x10b
# id vars doc_id text
# text1_1 1 top text1 this is text
# text1_2 2 down text1 so is this
# text1_3 3 top text1 and this is too.
# text2_1 1 top text2 we have more text here
# text2_2 2 down text2 and here too
# text2_3 3 top text2 and look at this, more text.
x10_corpus <- corpus(x10b)
summary(x10_corpus)
# Corpus consisting of 6 documents:
#
# Text Types Tokens Sentences id vars doc_id
# text1_1 3 3 1 1 top text1
# text1_2 3 3 1 2 down text1
# text1_3 5 5 1 3 top text1
# text2_1 5 5 1 1 top text2
# text2_2 3 3 1 2 down text2
# text2_3 8 8 1 3 top text2
#
# Source: /Users/kbenoit/Dropbox (Personal)/GitHub/lse-my459/assignment-2/* on x86_64 by kbenoit
# Created: Tue Feb 6 19:06:07 2018
# Notes:
方法2：制作两个语料库对象并合并
在这里，我们分别创建两个语料库对象，并使用
+运算符将它们合并。x10_corpus2 <-
corpus(x10[, -which(names(x10)=="text2")], text_field = "text1") +
corpus(x10[, -which(names(x10)=="text1")], text_field = "text2")
summary(x10_corpus2)
# Corpus consisting of 6 documents:
#
# Text Types Tokens Sentences id vars
# text1 3 3 1 1 top
# text2 3 3 1 2 down
# text3 5 5 1 3 top
# text11 5 5 1 1 top
# text21 3 3 1 2 down
# text31 8 8 1 3 top
#
# Source: Combination of corpuses corpus(x10[, -which(names(x10) == "text2")], text_field = "text1") and corpus(x10[, -which(names(x10) == "text1")], text_field = "text2")
# Created: Tue Feb 6 19:14:14 2018
# Notes:
您也可以在此阶段使用
docnames(x10_corpus2) <-重新分配文档名，使其更像第一种方法。关于r - 如何从具有多列文本的data.frame创建Quanteda语料库？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/48649343/