R: How to separate multiple choice, multiple answers questionnaire data that Google Forms put in one variable? [duplicate]

问题

I have run a survey using Google Forms. I downloaded the response dataset as a spreadsheet, but unfortunately when it comes to multiple choice, multiple anwsers responses, the data looks something like this:

Q1   Q2        Q3
1   "A, B ,C"  S 
2   "C, D"     T
1   "A, C, E"  U
3   "D"        V
2   "B, E"     Z

I would like to have it in a form similar to the below:

Q1  Q2        Q2A Q2B Q2C Q2D Q2E   Q3
1   "A, B, C"  1   1   1   0   0     S
2   "C, D"     0   0   1   1   0     T
1   "A, C, E"  1   0   1   0   1     U
3   "D"        0   0   0   1   0     V
2   "B, E"     0   1   0   0   1     Z

Is there a clever way to do this? I have several multiple choice, multiple answers questions and more than 250 respondents, so I'd like to be able to do it easily.

Thanks in advance.

回答1:

Using dplyr and tidyr packages:

 dat %>% 
    separate(Q2, paste0("v", 1:5), remove=F) %>% 
    gather(q2, val, v1:v5) %>% 
    na.exclude %>% 
    mutate(val=paste0("Q2", val), q2=1) %>% 
    spread(val, q2) %>%
    select(Q1:Q2, Q2A:Q2E, Q3) %>%
    mutate_at(vars(Q2A:Q2E), .funs=funs(replace(., is.na(.), 0)))


  Q1      Q2 Q2A Q2B Q2C Q2D Q2E Q3
1  1 A, B ,C   1   1   1   0   0  S
2  1 A, C, E   1   0   1   0   1  U
3  2    B, E   0   1   0   0   1  Z
4  2    C, D   0   0   1   1   0  T
5  3       D   0   0   0   1   0  V

Input data:

dat <- structure(list(Q1 = c(1L, 2L, 1L, 3L, 2L), Q2 = structure(c(1L, 
4L, 2L, 5L, 3L), .Label = c("A, B ,C", "A, C, E", "B, E", "C, D", 
"D"), class = "factor"), Q3 = structure(1:5, .Label = c("S", 
"T", "U", "V", "Z"), class = "factor")), .Names = c("Q1", "Q2", 
"Q3"), class = "data.frame", row.names = c(NA, -5L))

来源：https://stackoverflow.com/questions/44109108/r-how-to-separate-multiple-choice-multiple-answers-questionnaire-data-that-goo

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