一、利用webbrowser.open()打開一個網站:
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實例:使用腳本打開一個網頁。
所有Python程序的第一行都應以#!python開頭,它告訴計算機想讓Python來執行這個程序。(我沒帶這行試了試,也可以,可能這是一種規范吧)
1.從sys.argv讀取命令行參數:打開一個新的文件編輯器窗口,輸入下面的代碼,將其保存為map.py。
2.讀取剪貼板內容:
3.調用webbrowser.open()函數打開外部瀏覽:
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#! python3
import
webbrowser, sys, pyperclip
if
len
(sys.argv) >
1
:
mapAddress
=
''.join(sys.argv[
1
:])
else
:
mapAddress
=
pyperclip.paste()
|
注:不清楚sys.argv用法的,請參考這里;不清楚.join()用法的,請參考這里。sys.argv是字符串的列表,所以將它傳遞給join()方法返回一個字符串。
好了,現在選中'天安門廣場'這幾個字並復制,然后到桌面雙擊你的程序。當然你也可以在命令行找到你的程序,然后輸入地點。
二、用requests模塊從Web下載文件:requests模塊不是Python自帶的,通過命令行運行pip install request安裝。沒翻牆是很難安裝成功的,手動安裝可以參考這里。
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>>>
import
requests
>>>
type
(res)
#響應對象
<
class
'requests.models.Response'
>
>>>
print
(res.status_code)
#響應碼
200
>>> res.text
#返回的文本
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requests中查看網上下載的文件內容的方法還有很多,如果以后的博客用的到,會做說明,在此不再一一介紹。在下載文件的過程中,用raise_for_status()方法可以確保下載確實成功,然后再讓程序繼續做其他事情。
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import
requests
try
:
res.raise_for_status()
except
Exception as exc:
print
(
'There was a problem: %s'
%
(exc))
|
三、將下載的文件保存到本地:
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>>>
import
requests
>>> res
=
requests.get(
'http://tech.firefox.sina.com/17/0820/10/6DKQALVRW5JHGE1I.html##0-tsina-1-13074-397232819ff9a47a7b7e80a40613cfe1'
)
>>> res.raise_for_status()
>>>
file
=
open
(
'1.txt'
,
'wb'
)
#以寫二進制模式打開文件,目的是保存文本中的“Unicode編碼”
>>>
for
word
in
res.iter_content(
100000
):
#<span class="fontstyle0"><span class="fontstyle0">iter_content()</span><span class="fontstyle1">方法在循環的每次迭代中返回一段</span><span class="fontstyle0">bytes</span><span class="fontstyle1">數據</span><span class="fontstyle1">類型的內容,你需要指定其包含的字節數</span></span>
file
.write(word)
16997
>>>
file
.close()
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四、用BeautifulSoup模塊解析HTML:在命令行中用pip install beautifulsoup4安裝它。
1.bs4.BeautifulSoup()函數可以解析HTML網站鏈接requests.get(),也可以解析本地保存的HTML文件,直接open()一個本地HTML頁面。
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>>>
import
requests, bs4
>>> res.raise_for_status()
>>> soup
=
bs4.BeautifulSoup(res.text)
Warning (
from
warnings module):
File
"C:\Users\King\AppData\Local\Programs\Python\Python36-32\lib\site-packages\beautifulsoup4-4.6.0-py3.6.egg\bs4\__init__.py"
, line
181
markup_type
=
markup_type))
UserWarning: No parser was explicitly specified, so I
'm using the best available HTML parser for this system ("html.parser"). This usually isn'
t a problem, but
if
you run this code on another system,
or
in
a different virtual environment, it may use a different parser
and
behave differently.
The code that caused this warning
is
on line
1
of the
file
<string>. To get rid of this warning, change code that looks like this:
BeautifulSoup(YOUR_MARKUP})
to this:
BeautifulSoup(YOUR_MARKUP,
"html.parser"
)
>>> soup
=
bs4.BeautifulSoup(res.text,
'html.parser'
)
>>>
type
(soup)
<
class
'bs4.BeautifulSoup'
>
|
我這里有錯誤提示,所以加了第二個參數。
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>>>
import
bs4
>>> html
=
open
(
'C:\\Users\\King\\Desktop\\1.htm'
)
>>> exampleSoup
=
bs4.BeautifulSoup(html)
>>> exampleSoup
=
bs4.BeautifulSoup(html,
'html.parser'
)
>>>
type
(exampleSoup)
<
class
'bs4.BeautifulSoup'
>
|
2.用select()方法尋找元素:需傳入一個字符串作為CSS“選擇器”來取得Web頁面相應元素,例如:
soup.select('div'):所有名為<div>的元素;
soup.select('#author'):帶有id屬性為author的元素;
soup.select('.notice'):所有使用CSS class屬性名為notice的元素;
soup.select('div span'):所有在<div>元素之內的<span>元素;
soup.select('input[name]'):所有名為<input>並有一個name屬性,其值無所謂的元素;
soup.select('input[type="button"]'):所有名為<input>並有一個type屬性,其值為button的元素。
想查看更多的解析器,請參看這里。
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>>>
import
requests, bs4
>>> res.raise_for_status()
>>> soup
=
bs4.BeautifulSoup(res.text,
'html.parser'
)
>>> author
=
soup.select(
'#author'
)
>>>
print
(author)
[]
>>>
type
(author)
<
class
'list'
>
>>> link
=
soup.select(
'link '
)
>>>
print
(link)
[<link href
=
"css/mozMainStyle-min.css?v=20170705"
rel
=
"external nofollow"
rel
=
"external nofollow"
rel
=
"stylesheet"
type
=
"text/css"
/
>, <link href
=
"
" id="
rel
=
"external nofollow"
rel
=
"external nofollow"
rel
=
"external nofollow"
moz
-
skin
" rel="
stylesheet
" type="
text
/
css
"/>, <link href="
" id="
rel
=
"external nofollow"
rel
=
"external nofollow"
rel
=
"external nofollow"
moz
-
dir
" rel="
stylesheet
" type="
text
/
css
"/>, <link href="
" id="
rel
=
"external nofollow"
rel
=
"external nofollow"
rel
=
"external nofollow"
moz
-
ver
" rel="
stylesheet
" type="
text
/
css"
/
>]
>>>
type
(link)
<
class
'list'
>
>>>
len
(link)
4
>>>
type
(link[
0
])
<
class
'bs4.element.Tag'
>
>>> link[
0
]
<link href
=
"css/mozMainStyle-min.css?v=20170705"
rel
=
"external nofollow"
rel
=
"external nofollow"
rel
=
"stylesheet"
type
=
"text/css"
/
>
>>> link[
0
].attrs
{
'rel'
: [
'stylesheet'
],
'type'
:
'text/css'
,
'href'
:
'css/mozMainStyle-min.css?v=20170705'
}
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3.通過元素的屬性獲取數據:接着上面的代碼寫。
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>>> link[
0
].get(
'href'
)
'css
/
mozMainStyle
-
min
.css?v
=
20170705
|
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