How to read Excel data by column name in python using xlrd

Question

I am trying to read the data of large excel file(almost 100000 row). I am using 'xlrd Module' in python to fetch the data from excel. I want to fetch data by column name(Cascade,Schedule Name,Market) instead of column number(0,1,2). Because my excel columns are not fixed. i know how to fetch data in case of fixed column.

here is the code by which i am fetching data from the excel for fixed column

import xlrd

file_location =r"C:\Users\Desktop\Vision.xlsx"
workbook=xlrd.open_workbook(file_location)
sheet= workbook.sheet_by_index(0)
print(sheet.ncols,sheet.nrows,sheet.name,sheet.number)

for i in range(sheet.nrows):
   flag = 0
   for j in range(sheet.ncols):
      value=sheet.cell(i,j).value

If anyone has any solution of this, kindly let me know

Thanks

Answer 1

Comment: still not working when header of
fieldnames = ['Cascade', 'Market', 'Schedule', 'Name] and
Sheet(['Cascade', 'Schedule', 'Name', 'Market']) are equal.

Keep order of fieldnames in col_idx, was not my initial goal.

---

Question: I want to fetch data by column name

The following OOP solution will work:

class OrderedByName():
    """
    Privides a generator method, to iterate in Column Name ordered sequence
    Provides subscription, to get columns index by name. using class[name]
    """
    def __init__(self, sheet, fieldnames, row=0):
        """
        Create a OrderedDict {name:index} from 'fieldnames'
        :param sheet: The Worksheet to use
        :param fieldnames: Ordered List of Column Names
        :param row: Default Row Index for the Header Row
        """
        from collections import OrderedDict
        self.columns = OrderedDict().fromkeys(fieldnames, None)
        for n in range(sheet.ncols):
            self.columns[sheet.cell(row, n).value] = n

    @property
    def ncols(self):
        """
        Generator, equal usage as range(xlrd.ncols), 
          to iterate columns in ordered sequence
        :return: yield Column index
        """
        for idx in self.columns.values():
            yield idx

    def __getitem__(self, item):
        """
        Make class object subscriptable
        :param item: Column Name
        :return: Columns index
        """
        return self.columns[item]

Usage:

# Worksheet Data
sheet([['Schedule', 'Cascade', 'Market'],
       ['SF05UB0', 'DO Macro Upgrade', 'Upper Cnetral Valley'],
       ['DE03HO0', 'DO Macro Upgrade', 'Toledo'],
       ['SF73XC4', 'DO Macro Upgrade', 'SF Bay']]
      )

# Instantiate with Ordered List of Column Names
# NOTE the different Order of Column Names
by_name = OrderedByName(sheet, ['Cascade', 'Market', 'Schedule'])

# Iterate all Rows and all Columns Ordered as instantiated
for row in range(sheet.nrows):
    for col in by_name.ncols:
        value = sheet.cell(row, col).value
        print("cell({}).value == {}".format((row,col), value))

Output:

cell((0, 1)).value == Cascade
cell((0, 2)).value == Market
cell((0, 0)).value == Schedule
cell((1, 1)).value == DO Macro Upgrade
cell((1, 2)).value == Upper Cnetral Valley
cell((1, 0)).value == SF05UB0
cell((2, 1)).value == DO Macro Upgrade
cell((2, 2)).value == Toledo
cell((2, 0)).value == DE03HO0
cell((3, 1)).value == DO Macro Upgrade
cell((3, 2)).value == SF Bay
cell((3, 0)).value == SF73XC4

---

Get Index of one Column by Name

print("cell{}.value == {}".format((1, by_name['Schedule']),
                                    sheet.cell(1, by_name['Schedule']).value))
#>>> cell(1, 0).value == SF05UB0

Tested with Python: 3.5