How Do I Change Column Content Based On Previous Row?

Apologies. Whenever I try to make them into tables rather than into code it seems to think I have a code embedded and won't let me post this. So here's an example of What I have H

Solution 1:

Edit Thanks to r2evans now without rowwise().

Perhaps this is what you are looking for:

library(dplyr)
library(tidyr)

df %>% 
  mutate(Begin_New = Map(seq, Begin, End -6000,list(by =1000)))%>% 
  unnest(Begin_New)%>% 
  group_by(ID, File, Period)%>% 
  mutate(End_New = ifelse(Begin_New +7000> End, End, Begin_New +6000))

returns

# A tibble: 428 x 10
   ID    File         Period   Begin   End Laser1 Laser2 Lead   Begin_New End_New
   <chr><chr><chr><dbl><dbl><chr><chr><chr><dbl><dbl>1 A01   longname.zip Baseline     030500 qfin   plethh plethi         060002 A01   longname.zip Baseline     030500 qfin   plethh plethi      100070003 A01   longname.zip Baseline     030500 qfin   plethh plethi      200080004 A01   longname.zip Baseline     030500 qfin   plethh plethi      300090005 A01   longname.zip Baseline     030500 qfin   plethh plethi      4000100006 A01   longname.zip Baseline     030500 qfin   plethh plethi      5000110007 A01   longname.zip Baseline     030500 qfin   plethh plethi      6000120008 A01   longname.zip Baseline     030500 qfin   plethh plethi      7000130009 A01   longname.zip Baseline     030500 qfin   plethh plethi      80001400010 A01   longname.zip Baseline     030500 qfin   plethh plethi      90001500011 A01   longname.zip Baseline     030500 qfin   plethh plethi     100001600012 A01   longname.zip Baseline     030500 qfin   plethh plethi     110001700013 A01   longname.zip Baseline     030500 qfin   plethh plethi     120001800014 A01   longname.zip Baseline     030500 qfin   plethh plethi     130001900015 A01   longname.zip Baseline     030500 qfin   plethh plethi     140002000016 A01   longname.zip Baseline     030500 qfin   plethh plethi     150002100017 A01   longname.zip Baseline     030500 qfin   plethh plethi     160002200018 A01   longname.zip Baseline     030500 qfin   plethh plethi     170002300019 A01   longname.zip Baseline     030500 qfin   plethh plethi     180002400020 A01   longname.zip Baseline     030500 qfin   plethh plethi     190002500021 A01   longname.zip Baseline     030500 qfin   plethh plethi     200002600022 A01   longname.zip Baseline     030500 qfin   plethh plethi     210002700023 A01   longname.zip Baseline     030500 qfin   plethh plethi     220002800024 A01   longname.zip Baseline     030500 qfin   plethh plethi     230002900025 A01   longname.zip Baseline     030500 qfin   plethh plethi     240003050026 A01   longname.zip Run      3050068500 qfin   plethh plethi     305003650027 A01   longname.zip Run      3050068500 qfin   plethh plethi     315003750028 A01   longname.zip Run      3050068500 qfin   plethh plethi     325003850029 A01   longname.zip Run      3050068500 qfin   plethh plethi     335003950030 A01   longname.zip Run      3050068500 qfin   plethh plethi     3450040500

I named the columns Begin_New and End_New, you could change that easily into Begin and End.