# PRTM: Calculating Protein Mass

In a weighted alphabet, every symbol is assigned a positive real number called a weight. A string formed from a weighted alphabet is called a weighted string, and its weight is equal to the sum of the weights of its symbols.

The standard weight assigned to each member of the 20-symbol amino acid alphabet is the monoisotopic mass of the corresponding amino acid.

Given: A protein string of length at most 1000 aa.

Return: The total weight of . Consult the monoisotopic mass table.

## Sample Dataset

```
SKADYEK
```

## Sample Output

```
821.392
```

# R

```
library(readr)
library(dplyr)
f <- "prtm.txt"
mmt <- read_csv("monoisotopic_mass_table.csv")
p <-
data_frame(
acid =
readLines(f) %>%
strsplit(split = "") %>%
unlist()
) %>%
left_join(mmt, by = "acid")
sum(p$mass) %>%
round(3) %>%
cat()
```

```
821.392
```