问题
I have a data frame with 4 columns. Column 1 consists of ID's, column 2 consists of texts (about 100 words each), column 3 and 4 consist labels.
Now I would like to retrieve word frequencies (of the most common words) from the texts column and add those frequencies as extra columns to the data frame. I would like the column names to be the words themselves and the columns filled with their frequencies (ranging from 0 to ... per text) in the texts.
I tried some functions of the tm package but until now unsatisfactory. Does anyone has any idea how to deal with this problem or where to start? Is there a package that can do the job?
id texts label1 label2
回答1:
Well let's work through the issues then...
I'm guessing you have a data.frame that looks like this:
person sex adult state code
1 sam m 0 Computer is fun. Not too fun. K1
2 greg m 0 No it's not, it's dumb. K2
3 teacher m 1 What should we do? K3
4 sam m 0 You liar, it stinks! K4
5 greg m 0 I am telling the truth! K5
6 sally f 0 How can we be certain? K6
7 greg m 0 There is no way. K7
8 sam m 0 I distrust you. K8
9 sally f 0 What are you talking about? K9
10 researcher f 1 Shall we move on? Good then. K10
11 greg m 0 I'm hungry. Let's eat. You already? K11
This data set comes from the qdap package. to get qdap use install.packages("qdap").
Now to make the reproducible example I was talking about with your data set do what I'm doing here with the DATA data set from qdap.
DATA
dput(head(DATA))
Ok now for your original problem I think wfm will do what you want:
freqs <- t(wfm(DATA$state, 1:nrow(DATA)))
data.frame(DATA, freqs, check.names = FALSE)
If you only wanted the top so many words use an ordering technique like I use here:
freqs <- t(wfm(DATA$state, 1:nrow(DATA)))
ords <- rev(sort(colSums(freqs)))[1:9] #top 9 words
top9 <- freqs[, names(ords)] #grab those columns from freqs
data.frame(DATA, top9, check.names = FALSE) #put it together
The outcome looks like this:
> data.frame(DATA, top9, check.names = FALSE)
person sex adult state code you we what not no it's is i fun
1 sam m 0 Computer is fun. Not too fun. K1 0 0 0 1 0 0 1 0 2
2 greg m 0 No it's not, it's dumb. K2 0 0 0 1 1 2 0 0 0
3 teacher m 1 What should we do? K3 0 1 1 0 0 0 0 0 0
4 sam m 0 You liar, it stinks! K4 1 0 0 0 0 0 0 0 0
5 greg m 0 I am telling the truth! K5 0 0 0 0 0 0 0 1 0
6 sally f 0 How can we be certain? K6 0 1 0 0 0 0 0 0 0
7 greg m 0 There is no way. K7 0 0 0 0 1 0 1 0 0
8 sam m 0 I distrust you. K8 1 0 0 0 0 0 0 1 0
9 sally f 0 What are you talking about? K9 1 0 1 0 0 0 0 0 0
10 researcher f 1 Shall we move on? Good then. K10 0 1 0 0 0 0 0 0 0
11 greg m 0 I'm hungry. Let's eat. You already? K11 1 0 0 0 0 0 0 0 0
来源：https://stackoverflow.com/questions/15258954/r-text-mining-how-to-change-texts-in-r-data-frame-column-into-several-columns