# DNA: Counting DNA Nucleotides

A string is simply an ordered collection of symbols selected from some alphabet and formed into a word; the length of a string is the number of symbols that it contains.

An example of a length 21 DNA string (whose alphabet contains the symbols ‘A’, ‘C’, ‘G’, and ‘T’) is “ATGCTTCAGAAAGGTCTTACG.”

Given: A DNA string of length at most 1000 nt.

Return: Four integers (separated by spaces) counting the respective number of times that the symbols ‘A’, ‘C’, ‘G’, and ‘T’ occur in .

## Sample Dataset

```
AGCTTTTCATTCTGACTGCAACGGGCAATATGTCTCTGTGTGGATTAAAAAAAGAGTGTCTGATAGCAGC
```

## Sample Output

```
20 12 17 21
```

# R

```
library(magrittr)
f <- "dna.txt"
sym <- c("A", "C", "G", "T")
readLines(f) %>%
strsplit(split = "") %>%
table() %>%
.[sym] %>%
unname() %>%
cat()
```

```
20 12 17 21
```