How do you get all the rows from a particular table using BeautifulSoup?
I am learning Python and BeautifulSoup to scrape data from the web, and read a HTML table. I can read it into 开发者_如何学PythonOpen Office and it says that it is Table #11.
It seems like BeautifulSoup is the preferred choice, but can anyone tell me how to grab a particular table and all the rows? I have looked at the module documentation, but can't get my head around it. Many of the examples that I have found online appear to do more than I need.
This should be pretty straight forward if you have a chunk of HTML to parse with BeautifulSoup. The general idea is to navigate to your table using the findChildren method, then you can get the text value inside the cell with the string property.
>>> from BeautifulSoup import BeautifulSoup
>>>
>>> html = """
... <html>
... <body>
... <table>
... <th><td>column 1</td><td>column 2</td></th>
... <tr><td>value 1</td><td>value 2</td></tr>
... </table>
... </body>
... </html>
... """
>>>
>>> soup = BeautifulSoup(html)
>>> tables = soup.findChildren('table')
>>>
>>> # This will get the first (and only) table. Your page may have more.
>>> my_table = tables[0]
>>>
>>> # You can find children with multiple tags by passing a list of strings
>>> rows = my_table.findChildren(['th', 'tr'])
>>>
>>> for row in rows:
... cells = row.findChildren('td')
... for cell in cells:
... value = cell.string
... print("The value in this cell is %s" % value)
...
The value in this cell is column 1
The value in this cell is column 2
The value in this cell is value 1
The value in this cell is value 2
>>>
If you ever have nested tables (as on the old-school designed websites), the above approach might fail.
As a solution, you might want to extract non-nested tables first:
html = '''<table>
<tr>
<td>Top level table cell</td>
<td>
<table>
<tr><td>Nested table cell</td></tr>
<tr><td>...another nested cell</td></tr>
</table>
</td>
</tr>
</table>'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html, 'lxml')
non_nested_tables = [t for t in soup.find_all('table') if not t.find_all('table')]
Alternatively, if you want to extract content of all the tables, including those that nest other tables, you can extract only top-level tr and th/td headers. For this, you need to turn off recursion when calling the find_all method:
soup = BeautifulSoup(html, 'lxml')
tables = soup.find_all('table')
cnt = 0
for my_table in tables:
cnt += 1
print ('=============== TABLE {} ==============='.format(cnt))
rows = my_table.find_all('tr', recursive=False) # <-- HERE
for row in rows:
cells = row.find_all(['th', 'td'], recursive=False) # <-- HERE
for cell in cells:
# DO SOMETHING
if cell.string: print (cell.string)
Output:
=============== TABLE 1 ===============
Top level table cell
=============== TABLE 2 ===============
Nested table cell
...another nested cell
The recursive is a great trick if you don't have nested tables, but if you do, then you need to do things one level at a time.
The one HTML variation that could bite you is the following where the tbody and or thead elements are also used.
html = '
<table class="fancy">
<thead>
<tr><th>Nested table cell</th></tr>
</thead>
<tbody>
<tr><td><table id=2>...another nested cell</table></td></tr>
</tbody>
</table>
</table>
in this situation, you will need to do the following
table = soup.find_all("table", {"class": "fancy"})[0]
thead = table.find_all('thead', recursive=False)
header = thead[0].findChildren('th')
tbody = table.find_all('tbody', recursive=False)
rows = tbody[0].find_all('tr', recursive=False)
now you have the head and rows
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