Successive sum of column only if another column has the good value in R












1















I currently have a dataframe looking like that (with time in seconds and Zone1 a boolean):



Time Zone1
1 0
3 0
4 1
5 1
6 1
7 0
9 1
10 1


I'd like to have the sum of values for successive criteria so I would get something like this:



Time Zone1 TimeInZone
1 0 NA
3 0 NA
4 1 2
5 1 2
6 1 2
7 0 NA
9 1 1
10 1 1


So like this



I can't find what to do, how can I deal with that?
Thanks.



EDITED: More accurate dataframe










share|improve this question

























  • So you want each row where Zone1 is true to have the length of the previous Zone1 run?

    – tstenner
    Nov 14 '18 at 20:15











  • Yes it's that, but your code is working, I'll mark it as a solution :)

    – Clément POIRET
    Nov 15 '18 at 14:57
















1















I currently have a dataframe looking like that (with time in seconds and Zone1 a boolean):



Time Zone1
1 0
3 0
4 1
5 1
6 1
7 0
9 1
10 1


I'd like to have the sum of values for successive criteria so I would get something like this:



Time Zone1 TimeInZone
1 0 NA
3 0 NA
4 1 2
5 1 2
6 1 2
7 0 NA
9 1 1
10 1 1


So like this



I can't find what to do, how can I deal with that?
Thanks.



EDITED: More accurate dataframe










share|improve this question

























  • So you want each row where Zone1 is true to have the length of the previous Zone1 run?

    – tstenner
    Nov 14 '18 at 20:15











  • Yes it's that, but your code is working, I'll mark it as a solution :)

    – Clément POIRET
    Nov 15 '18 at 14:57














1












1








1








I currently have a dataframe looking like that (with time in seconds and Zone1 a boolean):



Time Zone1
1 0
3 0
4 1
5 1
6 1
7 0
9 1
10 1


I'd like to have the sum of values for successive criteria so I would get something like this:



Time Zone1 TimeInZone
1 0 NA
3 0 NA
4 1 2
5 1 2
6 1 2
7 0 NA
9 1 1
10 1 1


So like this



I can't find what to do, how can I deal with that?
Thanks.



EDITED: More accurate dataframe










share|improve this question
















I currently have a dataframe looking like that (with time in seconds and Zone1 a boolean):



Time Zone1
1 0
3 0
4 1
5 1
6 1
7 0
9 1
10 1


I'd like to have the sum of values for successive criteria so I would get something like this:



Time Zone1 TimeInZone
1 0 NA
3 0 NA
4 1 2
5 1 2
6 1 2
7 0 NA
9 1 1
10 1 1


So like this



I can't find what to do, how can I deal with that?
Thanks.



EDITED: More accurate dataframe







r sum






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 14 '18 at 13:37







Clément POIRET

















asked Nov 14 '18 at 12:52









Clément POIRETClément POIRET

277




277













  • So you want each row where Zone1 is true to have the length of the previous Zone1 run?

    – tstenner
    Nov 14 '18 at 20:15











  • Yes it's that, but your code is working, I'll mark it as a solution :)

    – Clément POIRET
    Nov 15 '18 at 14:57



















  • So you want each row where Zone1 is true to have the length of the previous Zone1 run?

    – tstenner
    Nov 14 '18 at 20:15











  • Yes it's that, but your code is working, I'll mark it as a solution :)

    – Clément POIRET
    Nov 15 '18 at 14:57

















So you want each row where Zone1 is true to have the length of the previous Zone1 run?

– tstenner
Nov 14 '18 at 20:15





So you want each row where Zone1 is true to have the length of the previous Zone1 run?

– tstenner
Nov 14 '18 at 20:15













Yes it's that, but your code is working, I'll mark it as a solution :)

– Clément POIRET
Nov 15 '18 at 14:57





Yes it's that, but your code is working, I'll mark it as a solution :)

– Clément POIRET
Nov 15 '18 at 14:57












1 Answer
1






active

oldest

votes


















2














I'm not entirely sure, where the last two rows came from, but here's my take on it:



library(data.table)
df <- data.table(Value=c(3,4,1,1,2), Criteria=c(1,1,2,1,3))
# First, generate a logical vector that indicates if the criterium changed:
df[, changed:=c(TRUE, Criteria[-1] != Criteria[-length(Criteria)])]
# Then, calculate the cumulative sum to get an index:
df[, index:=cumsum(changed)]
# Calculate the sum for each level of index:
df[, Sum:=sum(Value), by=index]
# print everything:
print(df)


Result:



   Value Criteria changed index Sum
1: 3 1 TRUE 1 7
2: 4 1 FALSE 1 7
3: 1 2 TRUE 2 1
4: 1 1 TRUE 3 1
5: 2 3 TRUE 4 2


To have the sum of the last block, use some data.table magic:



setkey(df, index)
nextblocksums <- df[index!=max(index), .(index=index+1,nextBlockSum=Sum)]
df[ nextblocksums , LastBlocksSum:=i.nextBlockSum]





share|improve this answer


























  • Thanks, it's working but it appears that my dataframe was a bit more complicated than just sum, in fact I need a time so I updated my first post. The time is the difference between last and first value in the range. Do you have an idea?

    – Clément POIRET
    Nov 14 '18 at 13:45











  • I managed to get it work by replacing sum by doing the difference between last and first line of a df[df$index == i]$Time in a For loop! Thanks!

    – Clément POIRET
    Nov 15 '18 at 14:58











  • That works, but it's slow for anything but tiny amounts of data. See my edit for a faster solution.

    – tstenner
    Nov 15 '18 at 16:04











  • Hmm pretty complicated ahah, I've troubles understanding this and I'm getting NA in LastBlocksSum

    – Clément POIRET
    Nov 15 '18 at 18:39













  • Of course there's a NA in the first LastBlocksSum, because there's no previous block for that one :-) I've clarified the last step somewhat, just remember that with data.tables the first part (df[i, j]) can also be a join, try df[ nextblocksums, ] to see it in action.

    – tstenner
    Nov 16 '18 at 9:36











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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









2














I'm not entirely sure, where the last two rows came from, but here's my take on it:



library(data.table)
df <- data.table(Value=c(3,4,1,1,2), Criteria=c(1,1,2,1,3))
# First, generate a logical vector that indicates if the criterium changed:
df[, changed:=c(TRUE, Criteria[-1] != Criteria[-length(Criteria)])]
# Then, calculate the cumulative sum to get an index:
df[, index:=cumsum(changed)]
# Calculate the sum for each level of index:
df[, Sum:=sum(Value), by=index]
# print everything:
print(df)


Result:



   Value Criteria changed index Sum
1: 3 1 TRUE 1 7
2: 4 1 FALSE 1 7
3: 1 2 TRUE 2 1
4: 1 1 TRUE 3 1
5: 2 3 TRUE 4 2


To have the sum of the last block, use some data.table magic:



setkey(df, index)
nextblocksums <- df[index!=max(index), .(index=index+1,nextBlockSum=Sum)]
df[ nextblocksums , LastBlocksSum:=i.nextBlockSum]





share|improve this answer


























  • Thanks, it's working but it appears that my dataframe was a bit more complicated than just sum, in fact I need a time so I updated my first post. The time is the difference between last and first value in the range. Do you have an idea?

    – Clément POIRET
    Nov 14 '18 at 13:45











  • I managed to get it work by replacing sum by doing the difference between last and first line of a df[df$index == i]$Time in a For loop! Thanks!

    – Clément POIRET
    Nov 15 '18 at 14:58











  • That works, but it's slow for anything but tiny amounts of data. See my edit for a faster solution.

    – tstenner
    Nov 15 '18 at 16:04











  • Hmm pretty complicated ahah, I've troubles understanding this and I'm getting NA in LastBlocksSum

    – Clément POIRET
    Nov 15 '18 at 18:39













  • Of course there's a NA in the first LastBlocksSum, because there's no previous block for that one :-) I've clarified the last step somewhat, just remember that with data.tables the first part (df[i, j]) can also be a join, try df[ nextblocksums, ] to see it in action.

    – tstenner
    Nov 16 '18 at 9:36
















2














I'm not entirely sure, where the last two rows came from, but here's my take on it:



library(data.table)
df <- data.table(Value=c(3,4,1,1,2), Criteria=c(1,1,2,1,3))
# First, generate a logical vector that indicates if the criterium changed:
df[, changed:=c(TRUE, Criteria[-1] != Criteria[-length(Criteria)])]
# Then, calculate the cumulative sum to get an index:
df[, index:=cumsum(changed)]
# Calculate the sum for each level of index:
df[, Sum:=sum(Value), by=index]
# print everything:
print(df)


Result:



   Value Criteria changed index Sum
1: 3 1 TRUE 1 7
2: 4 1 FALSE 1 7
3: 1 2 TRUE 2 1
4: 1 1 TRUE 3 1
5: 2 3 TRUE 4 2


To have the sum of the last block, use some data.table magic:



setkey(df, index)
nextblocksums <- df[index!=max(index), .(index=index+1,nextBlockSum=Sum)]
df[ nextblocksums , LastBlocksSum:=i.nextBlockSum]





share|improve this answer


























  • Thanks, it's working but it appears that my dataframe was a bit more complicated than just sum, in fact I need a time so I updated my first post. The time is the difference between last and first value in the range. Do you have an idea?

    – Clément POIRET
    Nov 14 '18 at 13:45











  • I managed to get it work by replacing sum by doing the difference between last and first line of a df[df$index == i]$Time in a For loop! Thanks!

    – Clément POIRET
    Nov 15 '18 at 14:58











  • That works, but it's slow for anything but tiny amounts of data. See my edit for a faster solution.

    – tstenner
    Nov 15 '18 at 16:04











  • Hmm pretty complicated ahah, I've troubles understanding this and I'm getting NA in LastBlocksSum

    – Clément POIRET
    Nov 15 '18 at 18:39













  • Of course there's a NA in the first LastBlocksSum, because there's no previous block for that one :-) I've clarified the last step somewhat, just remember that with data.tables the first part (df[i, j]) can also be a join, try df[ nextblocksums, ] to see it in action.

    – tstenner
    Nov 16 '18 at 9:36














2












2








2







I'm not entirely sure, where the last two rows came from, but here's my take on it:



library(data.table)
df <- data.table(Value=c(3,4,1,1,2), Criteria=c(1,1,2,1,3))
# First, generate a logical vector that indicates if the criterium changed:
df[, changed:=c(TRUE, Criteria[-1] != Criteria[-length(Criteria)])]
# Then, calculate the cumulative sum to get an index:
df[, index:=cumsum(changed)]
# Calculate the sum for each level of index:
df[, Sum:=sum(Value), by=index]
# print everything:
print(df)


Result:



   Value Criteria changed index Sum
1: 3 1 TRUE 1 7
2: 4 1 FALSE 1 7
3: 1 2 TRUE 2 1
4: 1 1 TRUE 3 1
5: 2 3 TRUE 4 2


To have the sum of the last block, use some data.table magic:



setkey(df, index)
nextblocksums <- df[index!=max(index), .(index=index+1,nextBlockSum=Sum)]
df[ nextblocksums , LastBlocksSum:=i.nextBlockSum]





share|improve this answer















I'm not entirely sure, where the last two rows came from, but here's my take on it:



library(data.table)
df <- data.table(Value=c(3,4,1,1,2), Criteria=c(1,1,2,1,3))
# First, generate a logical vector that indicates if the criterium changed:
df[, changed:=c(TRUE, Criteria[-1] != Criteria[-length(Criteria)])]
# Then, calculate the cumulative sum to get an index:
df[, index:=cumsum(changed)]
# Calculate the sum for each level of index:
df[, Sum:=sum(Value), by=index]
# print everything:
print(df)


Result:



   Value Criteria changed index Sum
1: 3 1 TRUE 1 7
2: 4 1 FALSE 1 7
3: 1 2 TRUE 2 1
4: 1 1 TRUE 3 1
5: 2 3 TRUE 4 2


To have the sum of the last block, use some data.table magic:



setkey(df, index)
nextblocksums <- df[index!=max(index), .(index=index+1,nextBlockSum=Sum)]
df[ nextblocksums , LastBlocksSum:=i.nextBlockSum]






share|improve this answer














share|improve this answer



share|improve this answer








edited Nov 16 '18 at 9:34

























answered Nov 14 '18 at 13:07









tstennertstenner

6,32964277




6,32964277













  • Thanks, it's working but it appears that my dataframe was a bit more complicated than just sum, in fact I need a time so I updated my first post. The time is the difference between last and first value in the range. Do you have an idea?

    – Clément POIRET
    Nov 14 '18 at 13:45











  • I managed to get it work by replacing sum by doing the difference between last and first line of a df[df$index == i]$Time in a For loop! Thanks!

    – Clément POIRET
    Nov 15 '18 at 14:58











  • That works, but it's slow for anything but tiny amounts of data. See my edit for a faster solution.

    – tstenner
    Nov 15 '18 at 16:04











  • Hmm pretty complicated ahah, I've troubles understanding this and I'm getting NA in LastBlocksSum

    – Clément POIRET
    Nov 15 '18 at 18:39













  • Of course there's a NA in the first LastBlocksSum, because there's no previous block for that one :-) I've clarified the last step somewhat, just remember that with data.tables the first part (df[i, j]) can also be a join, try df[ nextblocksums, ] to see it in action.

    – tstenner
    Nov 16 '18 at 9:36



















  • Thanks, it's working but it appears that my dataframe was a bit more complicated than just sum, in fact I need a time so I updated my first post. The time is the difference between last and first value in the range. Do you have an idea?

    – Clément POIRET
    Nov 14 '18 at 13:45











  • I managed to get it work by replacing sum by doing the difference between last and first line of a df[df$index == i]$Time in a For loop! Thanks!

    – Clément POIRET
    Nov 15 '18 at 14:58











  • That works, but it's slow for anything but tiny amounts of data. See my edit for a faster solution.

    – tstenner
    Nov 15 '18 at 16:04











  • Hmm pretty complicated ahah, I've troubles understanding this and I'm getting NA in LastBlocksSum

    – Clément POIRET
    Nov 15 '18 at 18:39













  • Of course there's a NA in the first LastBlocksSum, because there's no previous block for that one :-) I've clarified the last step somewhat, just remember that with data.tables the first part (df[i, j]) can also be a join, try df[ nextblocksums, ] to see it in action.

    – tstenner
    Nov 16 '18 at 9:36

















Thanks, it's working but it appears that my dataframe was a bit more complicated than just sum, in fact I need a time so I updated my first post. The time is the difference between last and first value in the range. Do you have an idea?

– Clément POIRET
Nov 14 '18 at 13:45





Thanks, it's working but it appears that my dataframe was a bit more complicated than just sum, in fact I need a time so I updated my first post. The time is the difference between last and first value in the range. Do you have an idea?

– Clément POIRET
Nov 14 '18 at 13:45













I managed to get it work by replacing sum by doing the difference between last and first line of a df[df$index == i]$Time in a For loop! Thanks!

– Clément POIRET
Nov 15 '18 at 14:58





I managed to get it work by replacing sum by doing the difference between last and first line of a df[df$index == i]$Time in a For loop! Thanks!

– Clément POIRET
Nov 15 '18 at 14:58













That works, but it's slow for anything but tiny amounts of data. See my edit for a faster solution.

– tstenner
Nov 15 '18 at 16:04





That works, but it's slow for anything but tiny amounts of data. See my edit for a faster solution.

– tstenner
Nov 15 '18 at 16:04













Hmm pretty complicated ahah, I've troubles understanding this and I'm getting NA in LastBlocksSum

– Clément POIRET
Nov 15 '18 at 18:39







Hmm pretty complicated ahah, I've troubles understanding this and I'm getting NA in LastBlocksSum

– Clément POIRET
Nov 15 '18 at 18:39















Of course there's a NA in the first LastBlocksSum, because there's no previous block for that one :-) I've clarified the last step somewhat, just remember that with data.tables the first part (df[i, j]) can also be a join, try df[ nextblocksums, ] to see it in action.

– tstenner
Nov 16 '18 at 9:36





Of course there's a NA in the first LastBlocksSum, because there's no previous block for that one :-) I've clarified the last step somewhat, just remember that with data.tables the first part (df[i, j]) can also be a join, try df[ nextblocksums, ] to see it in action.

– tstenner
Nov 16 '18 at 9:36




















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