Python, sum of decimals-CodePudding

I want to split a string of letters into a bunch of triplets and assign numbers to each triplet and then find the sum of the numbers. I managed to code till the number assigning part. But not able to generate the sum.Lot of errors popping up. Please help. P.S. I am a biologist and know nothing about coding. This is my partial code:

gene_code = "abcdef"

split_strings = []
n  = 3
for index in range(0, len(gene_code), n):
    split_strings.append(gene_code[index : index   n])
print(split_strings)
import re
gene_code = gene_code.replace('abc','1.2,')
gene_code = gene_code.replace('def','2.3,')

print(gene_code)

the output is as follows

['abc', 'def']
1.2,2.3,

Now I want to get the sum of these numbers. Please help?

CodePudding user response：

You could create a dictionary of replacements. Note that the replacements need to be written as numbers, not as strings, to be able to do calculations. Once you have a list of numbers, you can call sum(list_of_numbers).

Here is some example code:

gene_code = "abcdef"
split_strings = [gene_code[i:i   3] for i in range(0, len(gene_code), 3)]
replacements = {'abc': 1.2, 'def': 2.3}
numbers = [replacements[s] for s in split_strings]
print(sum(numbers))

If some strings don't have a replacement, this code will give an error. You could add a test and replace those numbers with zero instead:

numbers = [0 if not s in replacements else replacements[s]
           for s in split_strings]

Note that the above code uses list comprehension. That way, a loop such as:

new_list = []
for item in old_list:
   new_list.append(func(item))

can be written as

new_list = [func(item) for item in old_list]

Once you're used to that notation, you'll notice it's easier to read and easier to maintain. It gets especially useful when you'd be working with lists of lists.