Filter list of object with condition in Python

Question

I have a list structure like this:

listpost =
[
   {
      "post_id":"01",
      "text":"abc",
      "time": datetime.datetime(2021, 8, 5, 15, 53, 19),
      "type":"normal",
   },
   {
      "post_id":"02",
      "text":"nothing",
      "time":datetime.datetime(2021, 8, 5, 15, 53, 19),
      "type":"normal",
   }
]

I want to filter the list by text in [text] key if only the [text] has "abc"

so the example will look like this

listpost =
[
   {
      "post_id":"01",
      "text":"abc",
      "time": datetime.datetime(2021, 8, 5, 15, 53, 19),
      "type":"normal",
   }
]

My code:

from facebook_scraper import get_posts

listposts = []

for post in get_posts("myhealthkkm", pages=1):
    listposts.append(post)
print(listposts)

What is your question? Why did you not use an if statement to only append post if post['text'] is equal to 'abc'? — mkrieger1
– mkrieger1, Commented Aug 5, 2021 at 9:22

ThePyGuy · Accepted Answer · 2021-08-05 09:25:06Z

13

Since you specifically asked about filtering the list you have, you can use filter builtin with lambda to filter out the elements from the list.

>>> list(filter(lambda x: x.get('text', '')=='abc', listpost))

[{'post_id': '01', 'text': 'abc', 'time': datetime.datetime(2021, 8, 5, 15, 53, 19), 'type': 'normal'}]

But I'd recommend to filter it out upfront before actually appending it to the list, to avoid unnecessary computations due to the need to re-iterate the items i.e. appending only the items that match the criteria.

Something like this:

for post in get_posts("myhealthkkm", pages=1):
    if <post match the condition>:
        listposts.append(post)  # append the post

answered Aug 5, 2021 at 9:25

ThePyGuy

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Comments

balderman · Accepted Answer · 2021-08-05 09:30:52Z

10

simple like that:

filtered_list = [e for e in listpost if e['text'] == 'abc']

answered Aug 5, 2021 at 9:30

balderman

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Comments

Tajinder Singh · Accepted Answer · 2021-08-05 09:29:04Z

4

If you want to filter elements that are exactly "abc"

new_list = [el for el in listpost if el["text"]=="abc"]

If you want to keep elements that starts with "abc"

new_list = [el for el in listpost if el["text"].startswith("abc")]

If you want to keep elements that contains the "abc" substring

new_list = [el for el in listpost if "abc" in el["text"]]

answered Aug 5, 2021 at 9:29

Tajinder Singh

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Comments

nakul · Accepted Answer · 2022-09-02 14:31:50Z

2

 list(filter(lambda x: x['text']=='abc', listpost))

Hope this works

answered Sep 2, 2022 at 14:31

nakul

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Comments

A.M. Ducu · Accepted Answer · 2021-08-05 09:28:57Z

1

A good pythonic solution is already given, but here's another solution closer to what you were trying:

from facebook_scraper import get_posts

listposts = []
wanted = "abc"  # wanted post
for post in get_posts("myhealthkkm", pages=1):
    if t:=post.get("text", "") == wanted:
        # print("Found", t)
        listposts.append(post) 
    else:
        pass
        # print("Not found")
print(listposts)

answered Aug 5, 2021 at 9:28

A.M. Ducu

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4 Comments

johnny2000 Over a year ago

What if i want to change the == to in ?. Cause i want to check if abc is contain inside the text key or not and not equal.

johnny2000 Over a year ago

When i put contain like thisif wanted in post.get("text", ""): it will keep showing two same element instead of one

A.M. Ducu Over a year ago

@johnny2000 the if wanted in post.get("text", ""): should work fine. In case of duplicates, you can always make the list a set and then back to list. I.e. s = set(current_list); new_list=list(s). This should only keep the unique elements.

johnny2000 Over a year ago

Just now i tried it worked ! But after a couple times it should me TypeError: argument of type 'NoneType' is not iterable

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