R programming, For loop, if else statement not returning correct calculation of median number

Question

I have a big dataframe summary2, containing different keywords, and dates from 2016-2020 for each keyword. So I created a loop for each company, so whenever it gets to 2016 in the dataframe it should start on the if loop. The strange thing is that the median is not correctly returned when getting to company 2 on line 269. Since I am using a median that requires the -4 weeks and +3 weeks of the hits. The first dates must use an if statement, to calculate only the available dates.

I am using the code below, but the median is not working correctly in the else statement. However the summary2$test & test2 is returning the correct number, so why is not the median(summary2$hits[i-4:i+3]), returning the correct number? If I use the summary2$test & summary2$test numbers manually for a median it returns the correct numbers.

The code

for (i in 1:nrow(summary2)) {
  
  if (summary2$date[i] < as.Date('2016-01-31')) {
    summary2$median[i] = median(summary2$hits[i:i+3])
  }
  else {
    summary2$median[i] = median(summary2$hits[i-4:i+3])
    summary2$test[i] = i-4
    summary2$test2[i] = i+3
  }
  
}

The dataframe:

line	keyword	hits	date	company	median	test	test2
1	apple	32	2016-01-03	apple	30.0	NA	NA
2	apple	30	2016-01-10	apple	28.0	NA	NA
3	apple	29	2016-01-17	apple	29.0	NA	NA
4	apple	30	2016-01-24	apple	31.0	NA	NA
5	apple	28	2016-01-31	apple	29.5	1	8
6	apple	29	2016-02-07	apple	29.0	2	9
523	icloud	72	2016-01-03	apple	65	NA	NA
524	icloud	69	2016-01-10	apple	66	NA	NA
525	icloud	66	2016-01-17	apple	62	1	8
526	icloud	65	2016-01-24	apple	66	NA	NA
527	icloud	66	2016-01-31	apple	28	523	530
528	icloud	62	2016-02-07	apple	28	524	531
529	icloud	66	2016-02-14	apple	28	525	532
530	icloud	66	2016-02-21	apple	28	526	533

Looks like there is some bug with line 525 as well.

Answer 1

I think you should use () when you use :, e.g.,

for (i in 1:nrow(summary2)) {
  
  if (summary2$date[i] < as.Date('2016-01-31')) {
    summary2$median[i] = median(summary2$hits[i:(i+3)])
  }
  else {
    summary2$median[i] = median(summary2$hits[(i-4):(i+3)])
    summary2$test[i] = i-4
    summary2$test2[i] = i+3
  }
  
}