网页抓取:收集信息后清空数据集

时间:2020-04-08 18:55:18

标签: python pandas web-scraping beautifulsoup

我想创建一个数据集,其中包含从网站抓取的信息。我在下面解释我做了什么以及预期的输出。我得到行和列的空数组,然后是整个数据集,我不明白原因。我希望你能帮助我。

1)创建一个只有一列的空数据框:此列应包含要使用的网址列表。

data_to_use = pd.DataFrame([], columns=['URL'])

2)从以前的数据集中选择网址。

select_urls=dataset.URL.tolist()

这组网址看起来像:

                             URL
0                     www.bbc.co.uk
1             www.stackoverflow.com           
2                       www.who.int
3                       www.cnn.com
4         www.cooptrasportiriolo.it
...                             ...

3)使用以下网址填充列:

data_to_use['URL']= select_urls
data_to_use['URLcleaned'] = data_to_use['URL'].str.replace('^(www\.)', '')

4)选择一个随机样本进行测试:列50中的前URL

data_to_use = data_to_use.loc[1:50, 'URL']

5)尝试抓取信息

import requests
import time
from bs4 import BeautifulSoup

urls= data_to_use['URLcleaned'].tolist()

ares = []

for u in urls: # in the selection there should be an error. I am not sure that I am selecting the rig
    print(u)
    url = 'https://www.urlvoid.com/scan/'+ u
    r = requests.get(url)
    ares.append(r)   

rows = []
cols = []

for ar in ares:
    soup = BeautifulSoup(ar.content, 'lxml')
    tab = soup.select("table.table.table-custom.table-striped")   
    try:
            dat = tab[0].select('tr')
            line= []
            header=[]
            for d in dat:
                row = d.select('td')
                line.append(row[1].text)
            new_header = row[0].text
            if not new_header in cols:
                cols.append(new_header)
            rows.append(line)
    except IndexError:
        continue

print(rows) # this works fine. It prints the rows. The issue comes from the next line

data_to_use = pd.DataFrame(rows,columns=cols)  

不幸的是,上述步骤有问题,因为我没有得到任何结果,而只有[]__

来自data_to_use = pd.DataFrame(rows,columns=cols)的错误:

ValueError: 1 columns passed, passed data had 12 columns

我的预期输出将是:

URL          Website Address   Last Analysis   Blacklist Status \  
bbc.co.uk          Bbc.co.uk         9 days ago       0/35
stackoverflow.com Stackoverflow.com  7 days ago      0/35

Domain Registration               IP Address       Server Location    ...
996-08-01 | 24 years ago       151.101.64.81    (US) United States    ...
2003-12-26 | 17 years ago      ...

最后,我应该将创建的数据集保存在csv文件中。

3 个答案:

答案 0 :(得分:1)

Yon只能使用熊猫来做到这一点。尝试以下代码。

urllist=[ 'bbc.co.uk','stackoverflow.com','who.int','cnn.com']

dffinal=pd.DataFrame()
for url in urllist:
    df=pd.read_html("https://www.urlvoid.com/scan/" + url + "/")[0]
    list = df.values.tolist()
    rows = []
    cols = []
    for li in list:
        rows.append(li[1])
        cols.append(li[0])
    df1=pd.DataFrame([rows],columns=cols)
    dffinal = dffinal.append(df1, ignore_index=True)

print(dffinal)
dffinal.to_csv("domain.csv",index=False)

Csv快照:

enter image description here

快照。

enter image description here

Csv文件。

enter image description here


由于某些网址未返回数据,因此用try..except阻止了

更新

urllist=['gov.ie','','who.int', 'comune.staranzano.go.it', 'cooptrasportiriolo.it', 'laprovinciadicomo.it', 'asufc.sanita.fvg.it', 'canale7.tv', 'gradenigo.it', 'leggo.it', 'urbanpost.it', 'monitorimmobiliare.it', 'comune.villachiara.bs.it', 'ilcittadinomb.it', 'europamulticlub.com']

dffinal=pd.DataFrame()
for url in urllist:
    try:
        df=pd.read_html("https://www.urlvoid.com/scan/" + url + "/")[0]
        list = df.values.tolist()
        rows = []
        cols = []
        for li in list:
            rows.append(li[1])
            cols.append(li[0])
        df1=pd.DataFrame([rows],columns=cols)
        dffinal = dffinal.append(df1, ignore_index=True)

    except:
        continue

print(dffinal)
dffinal.to_csv("domain.csv",index=False)

控制台

            Website Address  ...         Region
0                     Gov.ie  ...         Dublin
1                    Who.int  ...         Geneva
2    Comune.staranzano.go.it  ...        Unknown
3      Cooptrasportiriolo.it  ...        Unknown
4       Laprovinciadicomo.it  ...        Unknown
5                 Canale7.tv  ...        Unknown
6                   Leggo.it  ...          Milan
7               Urbanpost.it  ...  Ile-de-France
8      Monitorimmobiliare.it  ...        Unknown
9   Comune.villachiara.bs.it  ...        Unknown
10          Ilcittadinomb.it  ...        Unknown

[11 rows x 12 columns]

答案 1 :(得分:0)

只需添加到@KunduK的解决方案即可。您可以使用熊猫的.T(转置函数)压缩部分代码。

因此,您可以打开此部分:

df=pd.read_html("https://www.urlvoid.com/scan/" + url + "/")[0]
list = df.values.tolist()
rows = []
cols = []
for li in list:
    rows.append(li[1])
    cols.append(li[0])
df1=pd.DataFrame([rows],columns=cols)
dffinal = dffinal.append(df1, ignore_index=True)

简单地:

df=pd.read_html("https://www.urlvoid.com/scan/" + url + "/")[0].set_index(0).T
dffinal = dffinal.append(df, ignore_index=True)

答案 2 :(得分:0)

不考虑转换为csv,让我们这样尝试:

urls=['gov.ie', 'who.int', 'comune.staranzano.go.it', 'cooptrasportiriolo.it', 'laprovinciadicomo.it', 'asufc.sanita.fvg.it', 'canale7.tv', 'gradenigo.it', 'leggo.it', 'urbanpost.it', 'monitorimmobiliare.it', 'comune.villachiara.bs.it', 'ilcittadinomb.it', 'europamulticlub.com']
ares = []
for u in urls:
    url = 'https://www.urlvoid.com/scan/'+u
    r = requests.get(url)
    ares.append(r)

请注意,其中3个网址没有数据,因此数据框中应该只有11行。 下一个:

rows = []
cols = []
for ar in ares:
    soup = bs(ar.content, 'lxml')
    tab = soup.select("table.table.table-custom.table-striped")        
    if len(tab)>0:
        dat = tab[0].select('tr')
        line= []
        header=[]
        for d in dat:
            row = d.select('td')
            line.append(row[1].text)
            new_header = row[0].text
            if not new_header in cols:
                cols.append(new_header)
        rows.append(line)

my_df = pd.DataFrame(rows,columns=cols)   
my_df.info()

输出:

<class 'pandas.core.frame.DataFrame'>
RangeIndex: 11 entries, 0 to 10
Data columns (total 12 columns):
Website Address        11 non-null object
Last Analysis          11 non-null object
Blacklist Status       11 non-null object
Domain Registration    11 non-null object
Domain Information     11 non-null object
IP Address             11 non-null object
Reverse DNS            11 non-null object
ASN                    11 non-null object
Server Location        11 non-null object
Latitude\Longitude     11 non-null object
City                   11 non-null object
Region                 11 non-null object
dtypes: object(12)
memory usage: 1.2+ KB