How to check if previous week's data matches current week's data in R

I have a dataframe in R that contains a column with a specific character string and the week that data was obtained. I need to create a new column that returns a 0 or a 1 if the character string from the current week matches the character string from the previous week.

For example, trying to create the column "Match" below.

Thank you for your help!

Week     Data      Match
 1       Red         0
 2       Blue        0
 3       Blue        1
 4       Yellow      0
 5       Green       0
 6       Blue        0
 7       Blue        1
 8       Blue        1
 9       Green       0
 10      Yellow      0

Solution

On a slightly modified data set that includes non-consecutive Weeks, using diff to measure the distance and lag to test the matches.

library(dplyr)

df %>% 
  mutate(Match = (if_else(c(0, diff(Week)) == 1, Data == lag(Data), FALSE))*1)
   Week   Data Match
1     1    Red     0
2     2   Blue     0
3     3   Blue     1
4     4 Yellow     0
5     6  Green     0
6     7   Blue     0
7     8   Blue     1
8    10   Blue     0
9    11  Green     0
10   12 Yellow     0

mod. data

df <- structure(list(Week = c(1, 2, 3, 4, 6, 7, 8, 10, 11, 12), Data = c("Red", 
"Blue", "Blue", "Yellow", "Green", "Blue", "Blue", "Blue", "Green", 
"Yellow")), row.names = c(NA, -10L), class = "data.frame")