Animal.txt
January 12, 2021
Today’s task is from a beginning programmer, who starts with an input file called animal.txt:
There once was a Dog Wednesday he ate Apples Thursday he ate Apples Friday he ate Apples Saturday he ate carrots There once was a Bear Tuesday he ate carrots Wednesday he ate carrots Thursday he ate chicken
He wants to create this output:
Food: Apples Animals who ate it: 1 ======= Dog Food: Carrots Animals who ate it: 2 ======== Bear Dog Food: Chicken Animals who ate it: 1 ======== Bear
He gave a complicated awk solution that didn’t work; it produced duplicate lines of output in those cases
where the same animal ate the same food on multiple days.
Your task is to write a program to produces the desired transformation form input to output. When
you are finished, you are welcome to read or run a suggested solution, or to post your own solution or
discuss the exercise in the comments below.
A cute little exercise. I hope it’s not counted as cheating if I tackle it using Julia (1.5.2): https://pastebin.com/UDbyNBhQ
I really had no idea that bears ate carrots!
Here’s a solution in Python.
import sys from collections import defaultdict lookup = defaultdict(set) # maps foods to a set of animals with open(sys.argv[1]) as f: for line in f.readlines(): line = line.strip() if line.startswith('The'): # 'The' identifies 'There once ...' animal = line[17:].capitalize() # len('There once was a ') == 17 elif line: food = line[line.index(' ') + 8:].capitalize() # len(' he ate ') == 8 lookup[food].add(animal) for idx, (food, animals) in enumerate(lookup.items()): print(f'Food: {food} Animals who ate it: {len(animals)}') print('=======') for animal in animals: print(animal) if idx + 1 < len(lookup): print()Example usage:
Python
import re
inFile = open(‘animal.txt’)
dt = dict()
l = set()
f = ”
for line in inFile:
if re.match(“There once was a”, line):
if f:
dt[f] = l
f = line.split()[-1].capitalize()
l = set()
elif re.search(“he ate”, line):
s = line.split()[-1].capitalize()
l.add(s)
dt[f] = l
dtr = dict() #reverse dict
for k, v in dt.items():
for iv in v:
if iv in dtr:
dtr[iv].add(k)
else:
dtr[iv] = set([k])
for val in dtr:
print(‘\nFood: {} Animals who ate it: {}’.format(val, len(dtr[val])))
print(‘=======’)
for i in dtr[val]:
print(i)
ouch (
https://pastebin.com/yh2iQweK
Here’s an AWK version. The food names are capitalized, and the output sorted, to match the example.
/There once was a/ { animal = $5 } /he ate/ { foods[$4][animal] = 1 } END { PROCINFO["sorted_in"] = "@val_str_asc" for (f in foods) { printf "Food: %s Animals who ate it: %d\n", raiseCase(f), length(foods[f]) printf "========\n" for (a in foods[f]) { printf "%s\n", a } printf "\n" } } function raiseCase(s) { return toupper(substr(s, 1, 1)) substr(s, 2) }