average number of words in a character vector in R - r

Question

i'm trying to get the average number of words in my character vector in R
one <- c(9, 23, 43)
two <- c("this is a new york times article.", "short article.", "he went outside to smoke a cigarette.")
mydf <- data.frame(one, two)
mydf
# one two
# 1 9 this is a new york times article.
# 2 23 short article.
# 3 43 he went outside to smoke a cigarette.
i'm looking for a function that gives me the average number of words of character vector "two".
the output here should be 5.3333 (=(7+2+7)/3)

Answer 1

Here's a possibility with the qdap package:
library(qdap)
wc(mydf$two, FALSE)/nrow(mydf)
## [1] 5.333333
This is overkill but you could also do:
word_stats(mydf$two)
## all n.sent n.words n.char n.syl n.poly wps cps sps psps cpw spw pspw n.state proDF2 n.hapax n.dis grow.rate prop.dis
## 1 all 3 16 68 23 3 5.333 22.667 7.667 1 4.250 1.438 .188 3 1 12 2 .750 .125
And wps column is words per sentence.

Answer 2

Or gregexpr()
mean(sapply(mydf$two,function(x)length(unlist(gregexpr(" ",x)))+1))
[1] 5.333333

Answer 3

Hadley Wickham's stringr package provides possibly the easiest way for this:
library(stringr)
foo<- str_split(two, " ") # split each element of your vector by the space sign
sapply(foo,length) # just a quick test: how many words has each element?
sum(sapply(foo,length))/length(foo) # calculate sum and divide it by the length of your original object
[1] 5.333333

Answer 4

I'm sure there are some more elaborated methods available but you can use strsplit to split your strings at spaces into a character vector and count its length of elements.
mean(sapply(strsplit(as.character(mydf$two), "[[:space:]]+"), length))
# [1] 5.3333