Create multiple columns of values that are in second column and fill new data frame with number of occurences according to first column

Question

I am new to stack overflow and sorry if I am not asking question properly. I have two columns country and Year.

    INDIA 1970
    USA   1970
    USA   1971
    INDIA 1970
    .
    .
    UK    1972

I want new data frame like this and I need to fill it with occurrences.

            1970 1971 1972.... 
    INDIA    2
    USA      1     1
    UK                1

Please see https://stackoverflow.com/help/how-to-ask – andydavies May 26 '18 at 12:23 — andydavies, May 26 '18 at 12:23
multiple ways to do this, simplest is `table(df)` – Ronak Shah May 26 '18 at 13:10 — Ronak Shah, May 26 '18 at 13:10

score 3 · Answer 1 · answered May 26 '18 at 12:18

An option could be to use reshape2::dcast with fun.aggregate argument set as length:

library(reshape2)
dcast(df, Country~Year, length)
#   Country 1970 1971 1972
# 1   INDIA    2    0    0
# 2      UK    0    0    1
# 3     USA    1    1    0

Data:

df <- read.table(text = 
"Country Year
INDIA 1970
USA   1970
USA   1971
INDIA 1970
UK    1972",
header = TRUE, stringsAsFactors = FALSE)

Create multiple columns of values that are in second column and fill new data frame with number of occurences according to first column

1 Answers1