Review
You've covered a lot of stringr functions in this chapter:
As a review we've got a few tasks for you to do with some DNA sequences. We've put three sequences, corresponding to three genes, from the genome of Yersinia pestis – the bacteria that causes bubonic plague – into the vector genes.
Each string represents a gene, each character a particular nucleotide: Adenine, Cytosine, Guanine or Thymine.
We aren't going to tell you which function to use. It's up to you to choose the right one and specify the needed arguments. Good luck!
This exercise is part of the course
String Manipulation with stringr in R
Exercise instructions
- Find the number of nucleotides in each gene.
- Find the number of
A's that occur in each gene. - Return the sequences that contain the sequence
"TTTTTT". - Replace all the
As in the sequences with a_.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# Find the number of nucleotides in each sequence
___
# Find the number of A's occur in each sequence
___
# Return the sequences that contain "TTTTTT"
___
# Replace all the "A"s in the sequences with a "_"
___