Delete specific lists inside a list

Question

import xlsxwriter
import xlrd

excel = xlrd.open_workbook('C:/Users/sel/Desktop/5/Book1.xlsx')
sheet = excel.sheet_by_index(0)
all_data = []
for row_index in range(sheet.nrows):
    row = []
    for col_index in range(sheet.ncols):
        valor = sheet.cell(row_index,col_index).value
        if valor == '':
            for crange in sheet.merged_cells:
                rlo, rhi, clo, chi = crange
                if rlo <= row_index and row_index < rhi and clo <= col_index and col_index < chi:
                    valor = sheet.cell(rlo, clo).value
                    break
        row.append(valor)
    all_data.append(row)

The data in excel or all_data is [[2.0, 0.0, 30.0], [2.0, 1.0, 20.0], [2.0, 5.0, 52.0], [8.0, 2.0, 58.0], [8.0, 3.0, 67.0], [8.0, 4.0, 85.0], [15.0, 7.0, 75.0], [15.0, 8.0, 24.0], [15.0, 6.0, 16.0], [5.0, 7.0, 46.0], [5.0, 5.0, 75.0], [5.0, 7.0, 85.0]]

I want to remove the lists in which the first number is less than 8.

l=[]
for i in range(sheet.nrows):
    if all_data[i][0]<8:
        l.append(i)

l here is [0, 1, 2, 9, 10, 11] which specifies the position of lists to be removed. How do I remove those lists all at once? I tried the code below, but it did not work

for i in l:
    del(all_data[i])

    print(all_data)

Answer 1

In python, it is almost always easier to keep what you want than to remove what you do not want:

all_data = [d for d in all_data if d[0] >= 8]
#[[8.0, 2.0, 58.0], [8.0, 3.0, 67.0], ..., [15.0, 6.0, 16.0]]

There is no need for a list of indexes.

Answer 2

Simply don't append valor to the row when its first element is less than 8. This way you don't have to check all_data for the values later. No need to write the other two for loops or any list comprehension

import xlsxwriter
import xlrd

excel = xlrd.open_workbook('C:/Users/sel/Desktop/5/Book1.xlsx')
sheet = excel.sheet_by_index(0)
all_data = []
for row_index in range(sheet.nrows):
    row = []
    for col_index in range(sheet.ncols):
        valor = sheet.cell(row_index,col_index).value
        if valor == '':
            for crange in sheet.merged_cells:
                rlo, rhi, clo, chi = crange
                if rlo <= row_index and row_index < rhi and clo <= col_index and col_index < chi:
                    valor = sheet.cell(rlo, clo).value
                    break
        if valor[0] >= 8:
            row.append(valor)
    all_data.append(row)

Answer 3

this is one way of doing it.

all_data = [lst for index, lst in enumerate(all_data) if index not in l]