Reading rows from Excel sheet to list of lists using openpyxl

Question

I'm new to Python and working on a Excel sheet that i want to read using python. I want to read the rows into lists of lists. I've tried this using Openpyxl

rows_iter = ws.iter_rows(min_col = 1, min_row = 2, max_col = 11, max_row = ws.max_row)

val1 = [[cell.value for cell in row] for row in rows_iter]

But this gives me a single list of all the rows as lists inside.

I want to make make different lists consisting of 15 or 12 or 10 rows in them (depending on a condition).

Could you please help me. Here are the sample Excel file, obtained output and expected outputs. Expected output and obtained op . I'm not able to attach more than 2 attachments! Thanks in advance!

Answer 1

rows_iter = ws.iter_rows(min_col = 1, min_row = 2, max_col = 11, max_row = ws.max_row)

val_intermediate = [[cell.value for cell in list(row)] for row in rows_iter]

# This would be set to whatever cell value contains N
N = ws['A1'].value

# This splits your shallow list of lists into a list of N lists of lists (!)
val1 = [val_intermediate[j:j+N] for j in range(1,len(val_intermediate),N)]

Explanation: The first list comprehension will return a shallow list of lists. The second list comprehension converts your shallow list of lists into a group of lists of lists that are N entries long. To see how this works, consider this sample data:

In [1]: a = [['a','b','c'],['d','e','f'],['g','h','i'],['j','k','l'] ['m','n','o'],['p','q','r']]

In [2]: N=2; [a[j:j+N] for j in range(1,len(a),N)]

Out[2]:
[[['d', 'e', 'f'], ['g', 'h', 'i']],
 [['j', 'k', 'l'], ['m', 'n', 'o']],
 [['p', 'q', 'r']]]

In [3]: N=3; [a[j:j+N] for j in range(1,len(a),N)]

Out[3]:
[[['d', 'e', 'f'], ['g', 'h', 'i'], ['j', 'k', 'l']],
 [['m', 'n', 'o'], ['p', 'q', 'r']]]

The range(1,len(a),N) will create a sequence of integers from 1 to len(a) , skipping N numbers, so that's how you can pick the correct locations at which to split your shallow list of lists. It grabs N-1 items because of the [j:j+N] indexing.