POS counting number of verbs

Hi all,
I have 16630 Messages in my data frame and I would like to count number of verbs in each message, to do so I have the following code:
str(tar)
'data.frame': 16630 obs. of? 2 variables:
$ Message? ? ? ? ? ? : Factor w/ 13412 levels "","'alter database? datafile' needs to be executed",..: 11163 1 9715 10110 9683 11364 12952 2242 7153 6907 ...
$ group? ? ? ? ? ? ? ? ? ?: Factor w/ 16630 levels "1","2","3","4",..: 1 2 3 4 5 6 7 8 9 10 ...
tagPOS <-? function(x, ...) {+? ? ?s <- as.String(x)+? ? ?word_token_annotator <- Maxent_Word_Token_Annotator()+? ? ?a2 <- Annotation(1L, "sentence", 1L, nchar(s))+? ? ?a2 <- annotate(s, word_token_annotator, a2)+? ? ?a3 <- annotate(s, Maxent_POS_Tag_Annotator(), a2)+? ? ?a3w <- a3[a3$type == "word"]+? ? ?POStags <- unlist(lapply(a3w$features, `[[`, "POS"))+? ? ?POStagged <- paste(sprintf("%s/%s", s[a3w], POStags), collapse = " ")+? ? ?list(POStagged = POStagged, POStags = POStags)+ }> count_verbs <-function(x) {+? ? ?pos_tags <- tagPOS(x)$POStags+? ? ?sum(grepl("VB", pos_tags))+ }> library(dplyr)> tar %>%?+? ? ?group_by(group) %>%+? ? ?summarise(num_verbs = count_verbs(Message))
And here is the error I get:Error in summarise_impl(.data, dots) :?? Evaluation error: no word token annotations found.

Does anyone know about this error??Thanks for any help.Elahe
Hi Elahe,

First, please post in plain text and make sure the code in your message 
is properly formatted.

Second, please state which libraries you are using.

Third, your problem appears to be with empty Messages, this can be 
resolved as follows.

 >>>>>>>>>>>
tar <- data.frame(Message=c("","'alter database? datafile' needs to be 
executed"), group=c("1","2"),
 ????????????????? stringsAsFactors=TRUE)
str(tar)

library(openNLP)
library(NLP)

tagPOS <- function(x, ...) {
 ? s <- as.String(x)
 ? if(s=="") return(list())
 ? word_token_annotator <- Maxent_Word_Token_Annotator()
 ? a2 <- Annotation(1L, "sentence", 1L, nchar(s))
 ? a2 <- annotate(s, word_token_annotator, a2)
 ? a3 <- annotate(s, Maxent_POS_Tag_Annotator(), a2)
 ? a3w <- a3[a3$type == "word"]
 ? POStags <- unlist(lapply(a3w$features, `[[`, "POS"))
 ? POStagged <- paste(sprintf("%s/%s", s[a3w], POStags), collapse = " ")
 ? list(POStagged = POStagged, POStags = POStags)
}

count_verbs <-function(x) {
 ? pos_tags <- tagPOS(x)$POStags
 ? sum(grepl("VB", pos_tags))
}

library(dplyr)

tar %>% group_by(group) %>% summarise(num_verbs = count_verbs(Message))
<<<<<<<<<<<<<<<<

Rgds,
Robert
Hi all, I have 16630 Messages in my data frame and I would like to 
count number of verbs in each message, to do so I have the following 
code:
str(tar) 
'data.frame': 16630 obs. of? 2 variables: $ Message? ? ? ? ? ? : 
Factor w/ 13412 levels "","'alter database? datafile' needs to be 
executed",..: 11163 1 9715 10110 9683 11364 12952 2242 7153 6907 ... $ 
group? ? ? ? ? ? ? ? ? ?: Factor w/ 16630 levels "1","2","3","4",..: 1 
2 3 4 5 6 7 8 9 10 ...
tagPOS <-? function(x, ...) {+ ?s <- as.String(x)+? ? 
?word_token_annotator <- Maxent_Word_Token_Annotator()+? ? ?a2 <- 
Annotation(1L, "sentence", 1L, nchar(s))+? ? ?a2 <- annotate(s, 
word_token_annotator, a2)+? ? ?a3 <- annotate(s, 
Maxent_POS_Tag_Annotator(), a2)+? ? ?a3w <- a3[a3$type == "word"]+? ? 
?POStags <- unlist(lapply(a3w$features, `[[`, "POS"))+? ? ?POStagged 
<- paste(sprintf("%s/%s", s[a3w], POStags), collapse = " ")+? ? 
?list(POStagged = POStagged, POStags = POStags)+ }> count_verbs 
<-function(x) {+ ?pos_tags <- tagPOS(x)$POStags+? ? ?sum(grepl("VB", 
pos_tags))+ }> library(dplyr)> tar %>%?+ ?group_by(group) %>%+? ? 
?summarise(num_verbs = count_verbs(Message)) 
And here is the error I get:Error in summarise_impl(.data, dots) :?? 
Evaluation error: no word token annotations found. Does anyone know 
about this error??Thanks for any help.Elahe [[alternative HTML version 
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