Iterate over Worksheets, Rows, Columns

Try this,

from openpyxl import load_workbook
workbook = load_workbook('----------/dataset.xlsx')
sheet = workbook.active
row_count = sheet.max_row
for i in range(row_count):
   print(sheet.cell(row=i, column=2).value)

Read the OpenPyXL Documentation

Iteration over all worksheets in a workbook, for instance:

for n, sheet in enumerate(wb.worksheets):
    print('Sheet Index:[{}], Title:{}'.format(n, sheet.title))

Output:

Sheet Index:[0], Title: Sheet    
Sheet Index:[1], Title: Sheet1    
Sheet Index:[2], Title: Sheet2    

Iteration over all rows and columns in one Worksheet:

worksheet = workbook.get_sheet_by_name('Sheet')

for row_cells in worksheet.iter_rows():
    for cell in row_cells:
       print('%s: cell.value=%s' % (cell, cell.value) )

Output:

<Cell Sheet.A1>: cell.value=²234
<Cell Sheet.B1>: cell.value=12.5
<Cell Sheet.C1>: cell.value=C1
<Cell Sheet.D1>: cell.value=D1
<Cell Sheet.A2>: cell.value=1234
<Cell Sheet.B2>: cell.value=8.2
<Cell Sheet.C2>: cell.value=C2
<Cell Sheet.D2>: cell.value=D2  

Iteration over all columns of one row, for instance row==2:

for row_cells in worksheet.iter_rows(min_row=2, max_row=2):
    for cell in row_cells:
        print('%s: cell.value=%s' % (cell, cell.value) )  

Output:

<Cell Sheet.A2>: cell.value=1234  
<Cell Sheet.B2>: cell.value=8.2  
<Cell Sheet.C2>: cell.value=C2  
<Cell Sheet.D2>: cell.value=D2  

Iteration over all rows, only column 2:

for col_cells in worksheet.iter_cols(min_col=2, max_col=2):
    for cell in col_cells:
        print('%s: cell.value=%s' % (cell, cell.value))

Output:

<Cell Sheet.B1>: cell.value=12.5
<Cell Sheet.B2>: cell.value=8.2
<Cell Sheet.B3>: cell.value=9.8
<Cell Sheet.B4>: cell.value=10.1
<Cell Sheet.B5>: cell.value=7.7

Tested with Python:3.4.2 - openpyxl:2.4.1 - LibreOffice: 4.3.3.2