将存储在向量中的所有字符串粘贴到单个字符串中，这适用于列表中的每个字符串向量

Question

This is the begining of the sample code :

library(stringr)

Sentences_vector1 <- as.data.frame(rbind("toto a titi", "tata c m tztz itutu", "toto z titi l k tutu h tyty"), stringsAsFactors=F)
Sentences_vector2 <- as.data.frame(rbind("toto a titi", "tata c m tztz itutu", "toto z titi l k tutu h tyty"), stringsAsFactors=F)
Sentences_vectors <- cbind(Sentences_vector1, Sentences_vector2)

List_with_diff_nb_strings = str_match_all(Sentences_vectors$V1, "[a-zA-Z]{2,}")

And now, I'm trying to paste all strings stored in a vector into a single string, this for each string vectors in a list. Please note that the vectors have different lengths.

List_concacenated_strings = sapply(List_with_diff_nb_strings,function (x) base::paste(x, sep = " "))

Thus, I would like to get a result with a content similar as this one :

list(c("toto titi"), c("tata tztz tutu"), c("toto titi tutu tyty"))

... but it doesn't work since I cannot specify the columns as their numbers are different for each line (character vectors with different lengths) of the list.

Maybe it's due to the fact that in my true R code, the command :

str(List_with_diff_nb_strings[[3]])

returns :

chr [1:4, 1] "toto" "titi" "tutu" "tyty"

instead of a "simple" vector like this :

chr [1:4] "toto" "titi" "tutu" "tyty"

Can anybody help me? Thanks in advance.

Answer 1

Replace the respective line of code with the following:

List_concacenated_strings = as.list(sapply(List_with_diff_nb_strings,function (x) base::paste(x, sep = " ",collapse=" ")))

And you get your desired output:

[[1]]
[1] "toto titi"

[[2]]
[1] "tata tztz tutu"

[[3]]
[1] "toto titi tutu tyty"

PS: This should be on Stack Overflow