How to create a dictionary from a file with multiple lines - python-3.x

Question

I'm trying to create a dictionary from multiple lines in a file, for i.e.
grocery store
apples
banana
bread
shopping mall
movies
clothing stores
shoe stores
What I'm trying to do is make the first row of each section (i.e. grocery store and shopping mall) the keys and everything underneath (apple, banana, bread & movies, clothing stores, shoe stores respectively) the values. I've been fiddling around with the readline approach + while loop, but I haven't been able to figure it out. If anyone knows, please help. Thanks.

Answer 1

One solution is to store in a variable the boolean value for whether you're at the start of a section. I don't want to give away the exciting (?) ending, but you could start with is_first=True.
OK, I guess I do want to give away the ending after all. Here's what I had in mind, more or less:
with open(fname) as f:
content = f.readlines()
is_first = True
d = {}
for line in content:
if line == '\n':
is_first = True
elif is_first:
key = line
is_first = False
else:
if key not in d:
d.put(key, '')
d.put(key, d.get(key) + line)
is_first = False
I find it easier to plan the code that way. Of course you could also solve this without an is_first variable, especially if you've already gone through the exercise of doing it with an is_first variable. I think the following is correct, but I wasn't incredibly careful:
with open(fname) as f:
content = f.readlines()
d = {}
while content:
key, content = content[0], content[1:]
if key != '\n':
value, content = content[0], content[1:]
while value != '\n':
if key not in d:
d.put(key, '')
d.put(key, d.get(key) + value)
value, content = content[0], content[1:]

Answer 2

#minopret has already given a pedagogically useful answer, and one that's important for beginners to understand. In a sense, even some more seemingly-sophisticated approaches are often doing that under the hood -- using a kind of state machine, I mean -- so it's important to know.
But for the heck of it, I'll describe a higher-level approach. There's a handy function itertools.groupby which groups sequences into contiguous groups. In this case, we can define a group by a bunch of lines which aren't all empty -- bool(line) is False if the line is empty and True otherwise, and then build a dict from them.
from itertools import groupby
with open("shopdict.txt") as fin:
stripped = map(str.strip, fin)
grouped = (list(g) for k,g in groupby(stripped, bool) if k)
d = {g[0]: g[1:] for g in grouped}

Answer 3

from itertools import groupby
with open("shopdict.txt") as fin:
stripped = map(str.strip, fin)
d = {k: g for b, (k, *g) in groupby(stripped, bool) if b}
And here's a way just using for loops
d={}
with open("shopdict.txt") as fin:
for key in fin:
key = key.strip()
d[key] = []
for item in fin:
if item.isspace():
break
d[key].append(item.strip())