在BS4中获取'列表'对象没有属性错误

Question

I am new to bs4 and am trying to experiment by building a price bot for Crypto currencies. This is the code I have so far:

import requests
import bs4
import csv
from datetime import datetime

def remove_all_whitespace(x):
    try:
        x = x.replace(" ", "")
    except:
        pass
    return x

def trim_the_ends(x):
    try:
        x = x.strip(' \t\n\r')
    except:
        pass
    return x

def remove_unneeded_chars(x):
    try:
        x = x.replace("$", "").replace("RRP", "")
    except:
        pass
    return x

URL = ("https://coinmarketcap.com/assets/golem-network-tokens/")

response = requests.get(URL)

soup = bs4.BeautifulSoup(response.text)

price = soup.select("span#quote_price.text-large").get_text()

print (price)

But I am getting this error:

AttributeError: 'list' object has no attribute 'get_text'

What am I doing wrong? From my understanding the .select does not work with list items, but how am I pulling a list ?

Answer 1

Yes, soup.select() returns a list of matches; the selector can match 0 or more times.

If you wanted to retrieve just one match, use the soup.select_one() method, which returns the first match, or None if there are no matches:

price = soup.select_one("span#quote_price.text-large").get_text()

However, the page you loaded doesn't contain that information . The page instead uses Javascript to load data over AJAX. requests is not a browser and won't load external resources or execute Javascript code.

The page loads the prices from https://graphs.coinmarketcap.com/currencies/golem-network-tokens/ , load that instead:

>>> import requests
>>> r = requests.get('https://graphs.coinmarketcap.com/currencies/golem-network-tokens/')
>>> data = r.json()
>>> data['price_usd'][-1][1]
0.309104

The first element of each entry in that list is a timestamp in microseconds:

>>> from datetime import datetime
>>> datetime.fromtimestamp(data['price_usd'][-1][0] / 1000)
datetime.datetime(2017, 8, 29, 18, 34, 46)

You should probably use their published API instead however:

https://api.coinmarketcap.com/v1/ticker/golem-network-tokens/