tablas - hacer un dataframe en python

¿Cómo analizar una tabla HTML con filas de filas en Python?

Question

El problema

Estoy tratando de analizar una tabla HTML con filas de filas, como en, estoy tratando de analizar mi calendario universitario.

Me estoy topando con el problema en el que si la última fila contiene un intervalo de filas, a la siguiente fila le falta un TD donde el intervalo de filas ahora es el TD que falta.

No tengo ni idea de cómo explicar esto y espero poder analizar este programa.

Lo que intenté

Casi todo lo que puedo pensar.

El resultado que obtengo

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

Como puede ver, hay una clave vak con el valor PROJ-T en el fragmento de salida anterior, dag es 4 mientras que se supone que es 5 (también conocido como Friday / Vrijdag), como se ve aquí:

El resultado que quiero

Un dict () de Python que se parece al publicado anteriormente, pero con el valor correcto

Dónde:

• day / dag es un int de 1 ~ 5 que representa lunes ~ viernes
• block_start / blok_start es un int que representa cuando comienza el curso (Bloque de tiempo, lado izquierdo de la tabla)
• block_end / blok_eind es un int que representa en qué bloque finaliza el curso
• classroom / lokaal es el código del aula en el que se encuentra el curso
• teacher / leraar es la identificación del maestro
• course / vak es el ID del curso

Estructura HTML básica para los datos anteriores.

<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>

El código

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>

Pitón

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 1

Tal vez es mejor usar la función incorporada bs4 como " findAll " para analizar su tabla.

Puede utilizar el siguiente código:

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")

content=r.content
page = BeautifulSoup(content, "html")
table=page.find(''table'')
trs=table.findAll("tr", {},recursive=False)
tr_count=0
trs.pop(0)
final_table={}

for tr in trs:
    tds=tr.findAll("td", {},recursive=False)
    if tds:
        td_count=0
        tds.pop(0)
        for td in tds:
            if td.has_attr(''rowspan''):                              
                final_table[str(tr_count)+"-"+str(td_count)]=td.text.strip()
                if int(td.attrs[''rowspan''])==4:
                    final_table[str(tr_count+1)+"-"+str(td_count)]=td.text.strip()
                if final_table.has_key(str(tr_count)+"-"+str(td_count+1)):
                    td_count=td_count+1         
            td_count=td_count+1
        tr_count=tr_count+1

roster=[]
for i in range(0,10): #iterate over time
    for j in range(0,5): #iterate over day
        item=final_table[str(i)+"-"+str(j)]
        if len(item)!=0:    
            block_eind=i+1          

            try:
                if final_table[str(i+1)+"-"+str(j)]==final_table[str(i)+"-"+str(j)]:
                        block_eind=i+2
            except:
                pass

            try:
                lokaal=item.split(''/r/n /n/n'')[0]
                leraar=item.split(''/r/n /n/n'')[1].split(''/n /n/r/n'')[0]
                vak=item.split(''/n /n/r/n'')[1]
            except:
                lokaal=leraar=vak="---"

            dayroster = {
                "dag": j+1,
                "blok_start": i+1,
                "blok_eind": block_eind,
                "lokaal": lokaal,
                "leraar": leraar,
                "vak": vak
            }


            dayroster_double = {
                "dag": j+1,
                "blok_start": i,
                "blok_eind": block_eind,
                "lokaal": lokaal,
                "leraar": leraar,
                "vak": vak
            }

            #use to prevent double dict for same event
            if dayroster_double not in roster:
                roster.append(dayroster)

print (roster)

Answer 2

Tendrá que seguir las filas de las filas anteriores, una por columna.

Puede hacer esto simplemente copiando el valor entero de un intervalo de filas en un diccionario, y las filas subsiguientes disminuyen el valor del intervalo de filas hasta que caen a 1 (o podemos almacenar el valor entero menos 1 y caemos a 0 para facilitar la codificación). A continuación, puede ajustar los recuentos de tablas posteriores en función de las filas de filas anteriores.

Su tabla complica esto un poco al usar un intervalo predeterminado de tamaño 2, que se incrementa en pasos de dos, pero que puede volver fácilmente a números manejables al dividir por 2.

En lugar de usar selectores masivos de CSS, seleccione solo las filas de la tabla y vamos a iterar sobre ellas:

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 there is a rowspan here, adjust to find correct position
        daynum += rowspan_offset
        while rowspans.get(daynum, 0):
            rowspan_offset += 1
            rowspans[daynum] -= 1
            daynum += 1
        # now we have a correct day number for this cell, adjusted for
        # rowspanning cells.
        # update the rowspan accounting for this cell
        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

Esto produce la salida correcta:

[{''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''}]

Además, este código continuará funcionando incluso si los cursos abarcan más de 2 bloques , o solo un bloque; cualquier tamaño de rowpan es compatible.