Create lists using loops in Python

Question

I've been working on a webpage scraper and I would like to create separate lists containing different elements. There would have to be more than a 1000 lists and I am trying to run that through a for loop. I need the lists to be appropriately named according to the element in each particular iteration. I tried using globals() to achieve this but it only takes an int or a char and not a string. Is there a way to achieve this?

For an example: If people = ['John', 'James', 'Jane'] I need 3 lists named Johnlist=[] Jameslist=[] Janelist=[]

Below is what I tried but it returns an error asking for either an int or a char.

for p in people:
   names = #scrapedcontent
   globals()['%list' % p] = []
   for n in names:
      globals()['%list' % p].append(#scrapedcontent)

You don't need this. You want a dictionary. Having random names floating in your namespace is a design mistake that will make your life very difficult — roganjosh
– roganjosh, Commented Dec 29, 2021 at 10:34

Corralien · Accepted Answer · 2022-01-02 10:07:38Z

2

I strongly discourages you to use globals, locals or vars As suggested by @roganjosh, prefer to use dict:

from collections import defaultdict

people = defaultdict(list):
for p in people:
    for n in names:
        people[p].append(n)

Or

people = {}
for p in people:
    names = #scrapedcontent
    people[p] = names

DON'T USE THIS

for p in people:
    names = [] #scrapedcontent
    globals().setdefault(f'list_{p}', []).extend(names)

Output:

>>> list_John
[]

>>> list_James
[]

>>> list_Jane
[]

edited Jan 2, 2022 at 10:07

answered Dec 29, 2021 at 10:39

Corralien

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4 Comments

Glad Over a year ago

Great suggestion but the data wont work in this way. Each p in the people list has multiple names. its like a relationship list for example JohnList will contain James, Kim, Harry because John has a relation with these names. and I dont believe dictionaries are they way for this. Any other suggestions would really help a lot.

Corralien Over a year ago

@Glad. globals() returns a dict so a dict is the right way to do what you want and safe.

Corralien Over a year ago

@Glad. I updated my answer, can you check it please?

Glad Over a year ago

That worked! Thank you so much. I realize that its a bad practice but its just a personal project that I'm working on and I need a way to scrape all the data before I can start working on it.

EyaS · Accepted Answer · 2021-12-29 10:39:25Z

0

try to do it in a dict:

for example:

d = {}

for p in people:
  d[p] = []
  names = ...      
  d[p].extend(names)

answered Dec 29, 2021 at 10:39

EyaS

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1 Comment

Glad Over a year ago

Great suggestion but the data wont work in this way. Each p in the people list has multiple names. its like a relationship list for example JohnList will contain James, Kim, Harry because John has a relation with these names. and I dont believe dictionaries are they way for this. Any other suggestions would really help a lot.

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