R: Remove rows based on columns containing ? in the string

Question

MarkerName	Allele1	Allele2	Weight	Zscore	P-value	Direction
10:1167075	a	g	218.00	2.446	0.01446	?+
7:77652992	t	c	218.00	2.076	0.03789	?-
X:24811075	a	g	315.00	2.463	0.01378	+?
4:15645706	t	c	315.00	2.582	0.009817	-?
5:13478320	g	a	315.00	2.872	0.00222	++

I am trying to subset a data frame with this format to remove all rows that contain a ?. The issue that I am running into is that the +/- signs are being recognized as operator symbols and R is giving me the following error:

Error: invalid regular expression '?+', reason 'Invalid use of repetition operators'

My goal is to have a data frame that looks like this:

MarkerName	Allele1	Allele2	Weight	Zscore	P-value	Direction
5:13478320	g	a	315.00	2.872	0.002	++

`?` is a reserved character in regex, meaning the previous character/group is optional (0 or 1). You can escape it `"\\?"` or use `fixed=TRUE`. https://stackoverflow.com/a/22944075/3358272 is a good reference for things like that. — r2evans, Nov 02 '22 at 17:55

score 2 · Answer 1 · answered Nov 02 '22 at 17:47

This should do:

df %>% filter(str_detect(Direction,'\\?', negate = T))

Example:

d = tibble(a = 1:3, b = c('+?', '?+', '++'))

      a b    
  <int> <chr>
1     1 +?   
2     2 ?+   
3     3 ++ 


d %>% filter(str_detect(b,'\\?', negate = T))


      a b    
  <int> <chr>
1     3 ++

R: Remove rows based on columns containing ? in the string

1 Answers1