问题描述
我使用Quanteda构建文档术语矩阵:
DELETE
哪个产量:
library(quanteda)
mytext = "This is my old text"
dtm <- dfm(mytext,tolower=T)
convert(dtm,to="data.frame")
我需要使“新”文本(新语料库)适合我现有的dtm(使用相同的词汇,以便出现相同的矩阵列)
假设我的“新”文本/语料是:
doc_id this is my old text
1 text1 1 1 1 1 1
我如何使这个“新”文本/语料库适合现有的dtm词汇表,以便得到一个像这样的矩阵:
newtext = "This is my new text"
解决方法
在转换为data.frame之前,您需要dfm_match()
。
library(quanteda)
## Package version: 2.1.2
mytext <- c(oldtext = "This is my old text")
dtm_old <- dfm(mytext)
dtm_old
## Document-feature matrix of: 1 document,5 features (0.0% sparse).
## features
## docs this is my old text
## oldtext 1 1 1 1 1
newtext <- c(newtext = "This is my new text")
dtm_new <- dfm(newtext)
dtm_new
## Document-feature matrix of: 1 document,5 features (0.0% sparse).
## features
## docs this is my new text
## newtext 1 1 1 1 1
要进行匹配,请使用dfm_match()
使新dfm与旧功能的功能集和顺序保持一致:
dtm_matched <- dfm_match(dtm_new,featnames(dtm_old))
dtm_matched
## Document-feature matrix of: 1 document,5 features (20.0% sparse).
## features
## docs this is my old text
## newtext 1 1 1 0 1
convert(dtm_matched,to = "data.frame")
## doc_id this is my old text
## 1 newtext 1 1 1 0 1