iSeeDeadPixels iSeeDeadPixels - 2 months ago 7
Python Question

How to parse an HTML table with rowspans in Python?

The problem

I'm trying to parse an HTML table with rowspans in it, as in, I'm trying to parse my college schedule.

I'm running into the problem where if the last row contains a rowspan, the next row is missing a TD where the rowspan is now that TD that is missing.

I have no clue how to account for this and I hope to be able to parse this schedule.

What i tried

Pretty much everything i can think of.

The result I get


[
{
'blok_eind': 4,
'blok_start': 3,
'dag': 4, # Should be 5
'leraar': 'DOODF000',
'lokaal': 'ALK C212',
'vak': 'PROJ-T',
},
]


As you can see, there's a
vak
key with the value
PROJ-T
in the output snippet above,
dag
is
4
while it's supposed to be
5
(a.k.a Friday/Vrijdag), as seen here:

Table

The result I want

A Python dict() that looks like the one posted above, but with the right value

Where:


  • day
    /
    dag
    is an int from 1~5 representing Monday~Friday

  • block_start
    /
    blok_start
    is an int that represents when the course starts (Time block, left side of table)

  • block_end
    /
    blok_eind
    is an int that represent in what block the course ends

  • classroom
    /
    lokaal
    is the classroom's code the course is in

  • teacher
    /
    leraar
    is the teacher's ID

  • course
    /
    vak
    is the ID of the course



Basic HTML Structure for above data


<center>
<table>
<tr>
<td>
<table>
<tbody>
<tr>
<td>
<font>
TEACHER-ID
</font>
</td>
<td>
<font>
<b>
CLASSROOM ID
</b>
</font>
</td>
</tr>
<tr>
<td>
<font>
COURSE ID
</font>
</td>
</tr>
</tbody>
</table>
</td>
</tr>
</table>
</center>


The code

HTML

<CENTER><font size="3" face="Arial" color="#000000">
<BR></font>
<font size="6" face="Arial" color="#0000FF">
16AO4EIO1B
&nbsp;</font> <font size="4" face="Arial">
IO1B
</font>
<BR>
<TABLE border="3" rules="all" cellpadding="1" cellspacing="1">
<TR>
<TD align="center">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 align="center" nowrap="1">
<TABLE>
<TR>
<TD align="center" nowrap=1><font size="2" face="Arial" color="#000000">
Maandag 29-08
</font> </TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 align="center" nowrap="1">
<TABLE>
<TR>
<TD align="center" nowrap=1><font size="2" face="Arial">
Dinsdag 30-08
</font> </TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 align="center" nowrap="1">
<TABLE>
<TR>
<TD align="center" nowrap=1><font size="2" face="Arial">
Woensdag 31-08
</font> </TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 align="center" nowrap="1">
<TABLE>
<TR>
<TD align="center" nowrap=1><font size="2" face="Arial">
Donderdag 01-09
</font> </TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 align="center" nowrap="1">
<TABLE>
<TR>
<TD align="center" nowrap=1><font size="2" face="Arial">
Vrijdag 02-09
</font> </TD>
</TR>
</TABLE>
</TD>
</TR>
<TR>
<TD rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD align="center" rowspan="2" nowrap=1><font size="3" face="Arial">
<B>1</B>
</font> </TD>
<TD align="center" nowrap=1><font size="2" face="Arial">
8:30
</font> </TD>
</TR>
<TR>
<TD align="center" nowrap=1><font size="2" face="Arial">
9:20
</font> </TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=4 align="center" nowrap="1">
<TABLE>
<TR>
<TD width="50%" nowrap=1><font size="2" face="Arial">
BLEEJ002
</font> </TD>
<TD width="50%" nowrap=1><font size="2" face="Arial">
<B>ALK B021</B>
</font> </TD>
</TR>
<TR>
<TD colspan="2" width="50%" nowrap=1><font size="2" face="Arial">
WEBD
</font> </TD>
</TR>
</TABLE>
</TD>
</TR>
<TR>
</TR>
<TR>
<TD rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD align="center" rowspan="2" nowrap=1><font size="3" face="Arial">
<B>2</B>
</font> </TD>
<TD align="center" nowrap=1><font size="2" face="Arial">
9:20
</font> </TD>
</TR>
<TR>
<TD align="center" nowrap=1><font size="2" face="Arial">
10:10
</font> </TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=4 align="center" nowrap="1">
<TABLE>
<TR>
<TD width="50%" nowrap=1><font size="2" face="Arial">
BLEEJ002
</font> </TD>
<TD width="50%" nowrap=1><font size="2" face="Arial">
<B>ALK B021B</B>
</font> </TD>
</TR>
<TR>
<TD colspan="2" width="50%" nowrap=1><font size="2" face="Arial">
WEBD
</font> </TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
</TR>
<TR>
</TR>
<TR>
<TD rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD align="center" rowspan="2" nowrap=1><font size="3" face="Arial">
<B>3</B>
</font> </TD>
<TD align="center" nowrap=1><font size="2" face="Arial">
10:25
</font> </TD>
</TR>
<TR>
<TD align="center" nowrap=1><font size="2" face="Arial">
11:15
</font> </TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=4 align="center" nowrap="1">
<TABLE>
<TR>
<TD width="50%" nowrap=1><font size="2" face="Arial">
DOODF000
</font> </TD>
<TD width="50%" nowrap=1><font size="2" face="Arial">
<B>ALK C212</B>
</font> </TD>
</TR>
<TR>
<TD colspan="2" width="50%" nowrap=1><font size="2" face="Arial">
PROJ-T
</font> </TD>
</TR>
</TABLE>
</TD>
</TR>
<TR>
</TR>
<TR>
<TD rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD align="center" rowspan="2" nowrap=1><font size="3" face="Arial">
<B>4</B>
</font> </TD>
<TD align="center" nowrap=1><font size="2" face="Arial">
11:15
</font> </TD>
</TR>
<TR>
<TD align="center" nowrap=1><font size="2" face="Arial">
12:05
</font> </TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=4 align="center" nowrap="1">
<TABLE>
<TR>
<TD width="50%" nowrap=1><font size="2" face="Arial">
BLEEJ002
</font> </TD>
<TD width="50%" nowrap=1><font size="2" face="Arial">
<B>ALK B021B</B>
</font> </TD>
</TR>
<TR>
<TD colspan="2" width="50%" nowrap=1><font size="2" face="Arial">
MENT
</font> </TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
</TR>
<TR>
</TR>
<TR>
<TD rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD align="center" rowspan="2" nowrap=1><font size="3" face="Arial">
<B>5</B>
</font> </TD>
<TD align="center" nowrap=1><font size="2" face="Arial">
12:05
</font> </TD>
</TR>
<TR>
<TD align="center" nowrap=1><font size="2" face="Arial">
12:55
</font> </TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
</TR>
<TR>
</TR>
<TR>
<TD rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD align="center" rowspan="2" nowrap=1><font size="3" face="Arial">
<B>6</B>
</font> </TD>
<TD align="center" nowrap=1><font size="2" face="Arial">
12:55
</font> </TD>
</TR>
<TR>
<TD align="center" nowrap=1><font size="2" face="Arial">
13:45
</font> </TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=4 align="center" nowrap="1">
<TABLE>
<TR>
<TD width="50%" nowrap=1><font size="2" face="Arial">
JONGJ003
</font> </TD>
<TD width="50%" nowrap=1><font size="2" face="Arial">
<B>ALK B008</B>
</font> </TD>
</TR>
<TR>
<TD colspan="2" width="50%" nowrap=1><font size="2" face="Arial">
BURG
</font> </TD>
</TR>
</TABLE>
</TD>
</TR>
<TR>
</TR>
<TR>
<TD rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD align="center" rowspan="2" nowrap=1><font size="3" face="Arial">
<B>7</B>
</font> </TD>
<TD align="center" nowrap=1><font size="2" face="Arial">
13:45
</font> </TD>
</TR>
<TR>
<TD align="center" nowrap=1><font size="2" face="Arial">
14:35
</font> </TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=4 align="center" nowrap="1">
<TABLE>
<TR>
<TD width="50%" nowrap=1><font size="2" face="Arial">
FLUIP000
</font> </TD>
<TD width="50%" nowrap=1><font size="2" face="Arial">
<B>ALK B004</B>
</font> </TD>
</TR>
<TR>
<TD colspan="2" width="50%" nowrap=1><font size="2" face="Arial">
ICT algemeen Prakti
</font> </TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
</TR>
<TR>
</TR>
<TR>
<TD rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD align="center" rowspan="2" nowrap=1><font size="3" face="Arial">
<B>8</B>
</font> </TD>
<TD align="center" nowrap=1><font size="2" face="Arial">
14:50
</font> </TD>
</TR>
<TR>
<TD align="center" nowrap=1><font size="2" face="Arial">
15:40
</font> </TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=4 align="center" nowrap="1">
<TABLE>
<TR>
<TD width="50%" nowrap=1><font size="2" face="Arial">
KOOLE000
</font> </TD>
<TD width="50%" nowrap=1><font size="2" face="Arial">
<B>ALK B008</B>
</font> </TD>
</TR>
<TR>
<TD colspan="2" width="50%" nowrap=1><font size="2" face="Arial">
NED
</font> </TD>
</TR>
</TABLE>
</TD>
</TR>
<TR>
</TR>
<TR>
<TD rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD align="center" rowspan="2" nowrap=1><font size="3" face="Arial">
<B>9</B>
</font> </TD>
<TD align="center" nowrap=1><font size="2" face="Arial">
15:40
</font> </TD>
</TR>
<TR>
<TD align="center" nowrap=1><font size="2" face="Arial">
16:30
</font> </TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
</TR>
<TR>
</TR>
<TR>
<TD rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD align="center" rowspan="2" nowrap=1><font size="3" face="Arial">
<B>10</B>
</font> </TD>
<TD align="center" nowrap=1><font size="2" face="Arial">
16:30
</font> </TD>
</TR>
<TR>
<TD align="center" nowrap=1><font size="2" face="Arial">
17:20
</font> </TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
<TD colspan=12 rowspan=2 align="center" nowrap="1">
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
</TD>
</TR>
<TR>
</TR>
</TABLE>
<TABLE cellspacing="1" cellpadding="1">
<TR>
<TD valign=bottom> <font size="4" face="Arial" color="#0000FF"></TR></TABLE><font size="3" face="Arial">
Periode1 29-08-2016 (35) - 04-09-2016 (35) G r u b e r &amp; P e t t e r s S o f t w a r e
</font></CENTER>


Python

from pprint import pprint
from bs4 import BeautifulSoup
import requests

r = requests.get("http://rooster.horizoncollege.nl/rstr/ECO/AMR/400-ECO/Roosters/36"
"/c/c00025.htm")
daytable = {
1: "Maandag",
2: "Dinsdag",
3: "Woensdag",
4: "Donderdag",
5: "Vrijdag"
}
timetable = {
1: ("8:30", "9:20"),
2: ("9:20", "10:10"),
3: ("10:25", "11:15"),
4: ("11:15", "12:05"),
5: ("12:05", "12:55"),
6: ("12:55", "13:45"),
7: ("13:45", "14:35"),
8: ("14:50", "15:40"),
9: ("15:40", "16:30"),
10: ("16:30", "17:20"),
}

page = BeautifulSoup(r.content, "lxml")

roster = []
big_rows = 2
last_row_big = False
# There are 10 blocks, each made up out of 2 TR's, run through them
for block_count in range(2, 22, 2):
# There are 5 days, first column is not data we want
for day in range(2, 7):
dayroster = {
"dag": 0,
"blok_start": 0,
"blok_eind": 0,
"lokaal": "",
"leraar": "",
"vak": ""
}
# This selector provides the classroom
table_bold = page.select(
"html > body > center > table > tr:nth-of-type(" + str(block_count) + ") > td:nth-of-type(" + str(
day) + ") > table > tr > td > font > b")

# This selector provides the teacher's code and the course ID
table = page.select(
"html > body > center > table > tr:nth-of-type(" + str(block_count) + ") > td:nth-of-type(" + str(
day) + ") > table > tr > td > font")

# This gets the rowspan on the current row and column
rowspan = page.select(
"html > body > center > table > tr:nth-of-type(" + str(block_count) + ") > td:nth-of-type(" + str(
day) + ")")

try:
if table or table_bold and rowspan[0].attrs.get("rowspan") == "4":
last_row_big = True
# Setting end of class
dayroster["blok_eind"] = (block_count // 2) + 1
else:
last_row_big = False
# Setting end of class
dayroster["blok_eind"] = (block_count // 2)
except IndexError:
pass

if table_bold:
x = table_bold[0]
# Classroom ID
dayroster["lokaal"] = x.contents[0]

if table:
iter = 0
for x in table:
content = x.contents[0].lstrip("\r\n").rstrip("\r\n")
# Cell has data
if content != "":
# Set start of class
dayroster["blok_start"] = block_count // 2
# Set day of class
dayroster["dag"] = day - 1
if iter == 0:
# Teacher ID
dayroster["leraar"] = content
elif iter == 1:
# Course ID
dayroster["vak"] = content
iter += 1

if table or table_bold:
# Store the data
roster.append(dayroster)

# Remove duplicates
seen = set()
new_l = []
for d in roster:
t = tuple(d.items())
if t not in seen:
seen.add(t)
new_l.append(d)
pprint(new_l)

Answer

You'll have to track the rowspans on previous rows, one per column.

You could do this simply by copying the integer value of a rowspan into a dictionary, and subsequent rows decrement the rowspan value until it drops to 1 (or we could store the integer value minus 1 and drop to 0 for ease of coding). Then you can adjust subsequent table counts based on preceding rowspans.

Your table complicates this a little by using a default span of size 2, incrementing in steps of two, but that can easily be brought back to manageable numbers by dividing by 2.

Rather than use massive CSS selectors, select just the table rows and we'll iterate over those:

roster = []
rowspans = {}  # track rowspanning cells
# every second row in the table
rows = page.select('html > body > center > table > tr')[1:21:2]
for block, row in enumerate(rows, 1):
    # take direct child td cells, but skip the first cell:
    daycells = row.select('> td')[1:]
    rowspan_offset = 0
    for daynum, daycell in enumerate(daycells, 1):
        # rowspan handling; if this cell is actually a rowspan, adjust
        daynum += rowspan_offset
        if rowspans.get(daynum, 0):
            rowspan_offset += 1
            rowspans[daynum] -= 1
            daynum += 1
        # now we have a correct day number for this cell, adjusted with
        # rowspanning cells accounted for
        # update the rowspan accounting as needed
        rowspan = (int(daycell.get('rowspan', 2)) // 2) - 1
        if rowspan:
            rowspans[daynum] = rowspan

        texts = daycell.select("table > tr > td > font")
        if texts:
            # class info found
            teacher, classroom, course = (c.get_text(strip=True) for c in texts)
            roster.append({
                'blok_start': block,
                'blok_eind': block + rowspan,
                'dag': daynum,
                'leraar': teacher,
                'lokaal': classroom,
                'vak': course
            })

    # days that were skipped at the end due to a rowspan
    while daynum < 5:
        daynum += 1
        if rowspans.get(daynum, 0):
            rowspans[daynum] -= 1

This produces correct output:

[{'blok_eind': 2,
  'blok_start': 1,
  'dag': 5,
  'leraar': u'BLEEJ002',
  'lokaal': u'ALK B021',
  'vak': u'WEBD'},
 {'blok_eind': 3,
  'blok_start': 2,
  'dag': 3,
  'leraar': u'BLEEJ002',
  'lokaal': u'ALK B021B',
  'vak': u'WEBD'},
 {'blok_eind': 4,
  'blok_start': 3,
  'dag': 5,
  'leraar': u'DOODF000',
  'lokaal': u'ALK C212',
  'vak': u'PROJ-T'},
 {'blok_eind': 5,
  'blok_start': 4,
  'dag': 3,
  'leraar': u'BLEEJ002',
  'lokaal': u'ALK B021B',
  'vak': u'MENT'},
 {'blok_eind': 7,
  'blok_start': 6,
  'dag': 5,
  'leraar': u'JONGJ003',
  'lokaal': u'ALK B008',
  'vak': u'BURG'},
 {'blok_eind': 8,
  'blok_start': 7,
  'dag': 3,
  'leraar': u'FLUIP000',
  'lokaal': u'ALK B004',
  'vak': u'ICT algemeen  Prakti'},
 {'blok_eind': 9,
  'blok_start': 8,
  'dag': 5,
  'leraar': u'KOOLE000',
  'lokaal': u'ALK B008',
  'vak': u'NED'}]

Moreover, this code will continue to work even if courses span more than 2 blocks, or just one block; any rowspan size is supported.