为 R 中的不同特征分配权重

问题描述

是否可以在 R 中制定 DFM 之前为不同的特征分配权重?

Is it possible to assign weights to different features before formulating a DFM in R?

在 R 中考虑这个例子

Consider this example in R

str="苹果比香蕉好"mydfm=dfm(str, ignoreFeatures = stopwords("english"), verbose = FALSE)

DFM mydfm 看起来像:

DFM mydfm looks like:

docs apple better banana
text1  1      1     1

但是，我想事先分配权重(苹果:5，香蕉:3)，以便 DFM mydfm 看起来像:

But, I want to assign weights(apple:5, banana:3) beforehand, so that DFM mydfm looks like:

docs apple better banana
text1  5      1     3

推荐答案

我不这么认为，但是你可以很容易地做到:

I don't think so, however you can easily do it afterwards:

library(quanteda)
str <- "apple is better than banana"
mydfm <- dfm(str, ignoredFeatures = stopwords("english"), verbose = FALSE)
idx <- which(names(weights) %in% colnames(mydfm))
mydfm[, names(weights)[idx]] <-  mydfm[, names(weights)[idx]] %*% diag(weights[idx])
mydfm
# 1 x 3 sparse Matrix of class "dgCMatrix"
#        features
# docs    apple better banana
#   text1     5      1      3

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