выходной массив (KEY> VALUE) поля ввода

Вот небольшая функция, которая блокирует строки, подмножает первые десять слов и затем вставляет их обратно.

string_fun <- function(x) {
  ul = unlist(strsplit(x, split = "\\s+"))[1:10]
  paste(ul,collapse=" ")
}

string_fun(x)

df <- read.table(text = "Keyword,City(Column Header)
The length of the string should not be more than 10 is or are in,New York
The Keyword should be of specific length is or are in,Los Angeles
                 This is an experimental basis program string is or are in,Seattle
                 Please help me with getting only the first ten words is or are in,Boston", sep = ",", header = TRUE)

df <- as.data.frame(df)

Использование apply (функция ничего не делает во втором столбце)

df$Keyword <- apply(df[,1:2], 1, string_fun)

EDIT Возможно, это более общий способ использования функции.

df[,1] <- as.character(df[,1])
df$Keyword <- unlist(lapply(df[,1], string_fun))

print(df)
#                      Keyword                            City.Column.Header.
# 1    The length of the string should not be more than            New York
# 2  The Keyword should be of specific length is or are         Los Angeles
# 3  This is an experimental basis program string is or             Seattle
# 4      Please help me with getting only the first ten              Boston