CODEWITHSUNDEEP
pythonmerge
Depekker
Depekker

Reputation: 27

Merging 2 lists in Python

With my current script

from lxml import html
import requests
from bs4 import BeautifulSoup
import re
import csv
import itertools


r = requests.get("http://www.mediamarkt.be/mcs/productlist/_128-tot-150-cm-51-tot-59-,98952,501091.html?langId=-17")

soup = BeautifulSoup((r.content),'lxml')

links = soup.find_all("h2")

g_data = soup.find_all("div", {"class": "price small"})

for item in g_data:
    prijs =[item.text.encode("utf-8") for item in g_data]

for link in links:
    if "TV" in link.text:
        product = [link.text.encode("utf-8").strip() for link in links if "TV" in link.text]

for item in itertools.chain(prijs + product):
    print item

I'm getting a list with first all the "prijs" and below all the "products. for example: prijs prijs prijs product product product

I would like to get the following result Prijs Product

Prijs Product

Prijs Product

Thank you

Upvotes: 1

Views: 125

Answers (1)

timgeb
timgeb

Reputation: 78650

The nature of the problem seems to have little to do with your actual code, so in order to make this question useful for future readers I am going to give you a general answer using example lists.

Don't concatenate your two lists. Generate a list of pairs with zip, then flatten the result.

>>> lst1 = ['a1', 'a2', 'a3']
>>> lst2 = ['b1', 'b2', 'b3']
>>> [x for pair in zip(lst1, lst2) for x in pair]
['a1', 'b1', 'a2', 'b2', 'a3', 'b3']

The flattening looks a little bit nicer with itertools.chain.

>>> list(chain.from_iterable(zip(lst1, lst2)))
['a1', 'b1', 'a2', 'b2', 'a3', 'b3']

Alternatively, with unpacking:

>>> list(chain(*zip(lst1, lst2)))
['a1', 'b1', 'a2', 'b2', 'a3', 'b3']

Since you are using Python 2, all of the above could be made more memory efficient by using itertools.izip instead of zip (the former returns an iterator, the latter a list).

Upvotes: 2

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