R compare dates on next rows

Question

I have this dataframe in R

  raw_payment_id from_bank_account        amount posted_at 
           <int> <chr>                     <dbl> <date>    
1         620691 SK660900000000062087       20.0 2018-02-25
2         618433 SK660900000000062087       10.0 2018-02-27
3         623157 SK660900000000062087       10.0 2018-03-02
4         628236 SK300900000000506871      812.  2018-03-06
5         627899 SK300900000000506871      812.  2018-03-07
6         628966 SK660900000000062087       10.0 2018-03-09

My goal is to find if payment from same account and at same amount was posted within 3 days. And if yes, mark both payments with 1. So result would be.

  raw_payment_id from_bank_account        amount posted_at     test 
           <int> <chr>                     <dbl> <date>        <int> 
1         620691 SK660900000000062087       20.0 2018-02-25    0
2         618433 SK660900000000062087       10.0 2018-02-27    1
3         623157 SK660900000000062087       10.0 2018-03-02    1
4         628236 SK300900000000506871      812.  2018-03-06    1
5         627899 SK300900000000506871      812.  2018-03-07    1
6         628966 SK660900000000062087       10.0 2018-03-09    0

I can´t find a way how to do that, my tryings with lag/leads fails on fact that there could be only one payment from bank account.

Welcome to Stack Overflow! In the future please share you data in a [reproducible](https://stackoverflow.com/q/5963269/1422451) format per the [MCVE](https://stackoverflow.com/help/mcve) and [`r`](https://stackoverflow.com/tags/r/info) tag description, such as by using `dput()`. Cheers! — Hack-R, Jul 07 '18 at 21:24
Please post your code with `lag/lead` anyway, we can probably fix it, e.g. add a sentinel with `from_bank_account=NA`, or else handle the special case. — smci, Jul 07 '18 at 21:51

score 2 · Answer 1 · answered Jul 07 '18 at 21:42

library(dplyr)


df %>% 
  group_by(from_bank_account, amount) %>% 
  mutate(var = case_when(abs(as.Date(posted_at) - as.Date(lag(posted_at))) < 4 ~ 1, 
                         abs(as.Date(posted_at) - as.Date(lead(posted_at))) < 4 ~ 1,
                         TRUE ~ 0))

  raw_payment_id from_bank_account    amount posted_at    var
           <int> <fct>                 <dbl> <fct>      <dbl>
1         620691 SK660900000000062087    20. 2018-02-25    0.
2         618433 SK660900000000062087    10. 2018-02-27    1.
3         623157 SK660900000000062087    10. 2018-03-02    1.
4         628236 SK300900000000506871   812. 2018-03-06    1.
5         627899 SK300900000000506871   812. 2018-03-07    1.
6         628966 SK660900000000062087    10. 2018-03-09    0.

Hack-R · Answer 2 · 2018-07-07T21:46:26.017

library(dplyr)

# Within each accounts, how many transactions were the same amount
tmp <- mydat %>% 
  group_by(from_bank_account, amount) %>% 
  mutate(number_of_dupes = n()) %>% 
  filter(number_of_dupes > 1) # only keep duplicates

# remove dups > 3 days apart
tmp$dup <- 0

for(i in 1:nrow(tmp)){
  acct <- tmp$from_bank_account[i]
  n    <- tmp$number_of_dupes[i]

  if(length(tmp$dup[(abs(difftime(tmp$posted_at[i],tmp$posted_at,units = "days")) < 4)
                    & (tmp$from_bank_account == acct)]) > 1){
    tmp$dup[i] <- 1
  }
}
tmp <- tmp[tmp$dup==1,]

mydat$flag_duplicate <- ifelse(mydat$raw_payment_id %in% tmp$raw_payment_id,1,0)

  raw_payment_id    from_bank_account amount  posted_at flag_duplicate
1         620691 SK660900000000062087     20 2018-02-25              0
2         618433 SK660900000000062087     10 2018-02-27              1
3         623157 SK660900000000062087     10 2018-03-02              1
4         628236 SK300900000000506871    812 2018-03-06              1
5         627899 SK300900000000506871    812 2018-03-07              1
6         628966 SK660900000000062087     10 2018-03-09              0

R compare dates on next rows

2 Answers2