Мы можем использовать paste
в R
toString(do.call(paste, df))
или одним звонком
do.call(paste, c(df, list(collapse=", ")))
#[1] "1990 25 2.5 525.25, 1991 30 1.5 1001.25"
данные
df <- structure(list(Year = 1990:1991, max_T = c(25, 30), min_T = c(2.5,
1.5), Prcp = c(525.25, 1001.25)), .Names = c("Year", "max_T",
"min_T", "Prcp"), class = "data.frame", row.names = c(NA, -2L
))