Iterate over a list of strings in python

Question

I am trying to set up a data set that checks how often several different names are mentioned in a list of articles. So for each article, I want to know how often nameA, nameB and so forth are mentioned. However, I have troubles with iterating over the list.

My code is the following:

for element in list_of_names:
for i in list_of_articles:
    list_of_namecounts = len(re.findall(element, i))

list_of_names = a string with several names [nameA nameB nameC]
list_of_articles = a list with 40.000 strings that are articles

Example of article in list_of_articles:

Index: 1
Type: str
Size: Amsterdam - de financiële ...

the error i get is: expected string or buffer

I though that when iterating over the list of strings, that the re.findall command should work using lists like this, but am also fairly new to Python. Any idea how to solve my issue here?

Thank you!

`re` stands for regular expression. You are not using regular expressions. You are looking for `filter`. — trincot, Nov 28 '16 at 14:39
What type is element? What type is i? Debug it somehow, maybe using a print. — Moberg, Nov 28 '16 at 14:40

score 0 · Answer 1 · edited May 23 '17 at 11:53

0

If your list is ['apple', 'apple', 'banana'] and you want the result: number of apple = 2, then:

from collections import Counter

list_count = Counter(list_of_articles)

for element in list_of_names:
    list_of_namecounts = list_count[element]

And assuming list_of_namecounts is a list ¿?

list_of_namecounts = []
for element in list_of_names:
    list_of_namecounts.append(list_count[element])

See this for more understanding

edited May 23 '17 at 11:53

Community

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answered Nov 28 '16 at 14:46

EmilioK

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There's no reason to rebuild the `Counter` for every name. The constructor should be outside the loop. – Patrick Haugh Nov 28 '16 at 14:47
Fixed, too fast :) – EmilioK Nov 28 '16 at 14:51
Thanks Patrick Haugh and EmilioK. I tried the command, but it gives me an overall number of mentions rather than a number for each article. Is that correct? If so, can I adapt the code to get a count for each string (=article) within list_of_articles? – M.Metz Nov 28 '16 at 15:18
You mean that in 'Apple pie with apple' it should return 2 for apple? – EmilioK Nov 28 '16 at 15:22
@EmilioK yes exactly – M.Metz Nov 28 '16 at 15:25
Ok, understood, in your original code change `code`len(re.findall(element, i))`code` with `code`i.count(element)`code` – EmilioK Nov 28 '16 at 15:27

Iterate over a list of strings in python

1 Answers1