plot vertical stacking line based on time point in r -

my df this:

test id  c1  c2  c3  c4  c5  c6  c7    22 112 112 118 121 124 na  na b    22  77 89  85  89  88  95  100 c    22  67 85  76  77  77  84  92 d    22  58 81  73  75  79  84  95 

c1, c2, c3... represents different time points. each row represents different test in df, student 22 has been tested 5 times on test a, , 7 times on test b,c , d.

i intend use ggplot2 create vertically stacked line graph x-axis 4 tests, y-axis scores, , vertical stacking being based on time point. can me?

thanks!

may helps

library(tidyr) library(ggplot2)  gather(df, var, val, c1:c7) %>%              filter(!is.na(val)) %>%             ggplot(. , aes(x=test, y=val, fill=var))+             geom_bar(stat='identity') 

update

these options.

df1 <- gather(df, var, val, c1:c7) %>%                                 filter(!is.na(val))  ggplot(df1, aes(x=test, y=val, colour=var))+                 geom_area(aes(fill=var), position='stack') 

or

 ggplot(df1, aes(x=as.numeric(factor(test)), y=val, fill=var)) +                                       geom_area(position='stack') 

or

 group_by(df1, test) %>%     mutate(val1=cumsum(val)) %>%     ggplot(., aes(x=as.numeric(factor(test)), y=val1, color=var)) +      geom_line() +      xlab('test') +     ylab('score') +     scale_x_discrete(breaks=as.numeric(factor(df2$test)),               labels=df2$test) 

data

df <- structure(list(test = c("a", "b", "c", "d"), id = c(22l, 22l,  22l, 22l), c1 = c(112l, 77l, 67l, 58l), c2 = c(112l, 89l, 85l,  81l), c3 = c(118l, 85l, 76l, 73l), c4 = c(121l, 89l, 77l, 75l ), c5 = c(124l, 88l, 77l, 79l), c6 = c(na, 95l, 84l, 84l), c7 = c(na,  100l, 92l, 95l)), .names = c("test", "id", "c1", "c2", "c3",  "c4", "c5", "c6", "c7"), class = "data.frame", row.names = c(na, -4l))