Coding challenges on optimization and the knapsack problem — MIT problem set

Implement the function load_cows(filename). It should take in the name of the data text file as a string, read in its contents, and return a dictionary that maps cow names to their weights.

The aliens want to take home their mutant cows, which jump over the moon. Their spaceship has a weight limit, and somehow they have bred cows with only integer weights. The data for the cows to be transported is stored in ps1_cow_data.txt, and another set of cows for another separate transport is in ps1_cow_data_2.txt — two files for you to read from and test individually. (MIT also encourages you to write your own cow list files for testing; your function should work on any file in this format.)

You can expect the data to be formatted in pairs of x,y on each line, where x is the name of the cow and y is a number indicating how much the cow weighs in tons. Here are the first few lines of ps1_cow_data.txt:

Maggie,3
Herman,7
Betsy,9
...

You can assume that all the cows have unique names. The weights in the returned dictionary are integers, not strings.

Some functions that may be helpful: str.split, open, file.readline, file.close.

print(load_cows('ps1_cow_data.txt')['Maggie'])  # 3
print(load_cows('ps1_cow_data.txt')['Herman'])  # 7
print(load_cows('ps1_cow_data.txt')['Betsy'])  # 9
print(len(load_cows('ps1_cow_data.txt')))  # 10

Adapted for the browser: both of MIT's data files are written into the working directory before your code runs, so open('ps1_cow_data.txt') works as it would next to ps1a.py.