rosalind练习题二十

# Problem

# 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 P of length at most 1000 aa.

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

# Sample Dataset

# SKADYEK

# Sample Output

# 821.392

# 定义氨基酸单一同位素质量表的字典

mass_table = {

'A':71.03711, 'C':103.00919, 'D':115.02694, 'E':129.04259,

    'F':147.06841, 'G':57.02146, 'H':137.05891, 'I':113.08406,

    'K':128.09496, 'L':113.08406, 'M':131.04049, 'N':114.04293,

    'P':97.05276, 'Q':128.05858, 'R':156.10111, 'S':87.03203,

    'T':101.04768, 'V':99.06841, 'W':186.07931, 'Y':163.06333

}

# 输入蛋白质序列x

protein ="SKADYEK"

# 计算总重量

total_weight =0

for aain protein:

total_weight += mass_table[aa]

print("%.3f" % total_weight)