Python variable List population

Question

I'm trying to read some data from an excel file in python

I want to place the data into a 2D list

[[A,1,2...],[B,2,3...],[C,5,6...]]

where A, B, C are the col headers and the numbers are the rows in that column

right now I'm using just to test if this will work so i know the code doesn't do exactly what i said above

#Blank list array
product = []
k = 0
#Read in Data
for r in range(1,sheet.nrows):
    k += 1;
    product[k,1] = sheet.cell(r,1).value

im getting errors saying that list indices must be integers, not tuples is there a way to populate a list like this with a variable because I do not know how many rows a column might have in the excel file I've heard of dictionaries but from what I've read I don't think those would be the best option for me since they are more "key" "value" and i have multiple values for one "key"

You could accomplish this with a dictionary, see: http://stackoverflow.com/questions/5378231/python-list-to-dictionary-multiple-values-per-key — Andreas GS, Jun 12 '13 at 14:16
Andrea doesn't he/she already have his list populated in that one tho? I need to basically populate my list and I don't know how long it needs to be — shreddish, Jun 12 '13 at 14:24
@karthikr i changed product[k,1] to product[k][1] and i get that the list index is out of range — shreddish, Jun 12 '13 at 15:02
@Reddman - lost reception before I could finish. If you are having trouble reading in rows use the CSV module. Parse each row such that that values you get are appended to the proper lists- [A,..],[B,..] etc. You also want a list of lists it looks like. See this article [link](http://mail.python.org/pipermail/tutor/2000-January/000943.html) — Andreas GS, Jun 12 '13 at 15:44
@AndreaGS thank you for your help however I do not want to read CSV files I'm trying to read straight from an excel file — shreddish, Jun 12 '13 at 16:10

Michael Davis · Accepted Answer · 2013-06-12T17:51:29.700

2

A dictionary would work for you, as each value can be a list.

product = {}
for col in range(sheet.ncols):
    values = []
    for row in range(1, sheet.nrows):
        values.append(sheet.cell(row, col).value)
    product[sheet.cell(0, col)] = values

This would then allow you to access any column's list of values by the column label.

> print product['B']
> [1, 4, 2, 6, 7]

EDIT: Edited to change from parsing rows to columns instead.

edited Jun 12 '13 at 17:51

answered Jun 12 '13 at 14:36

Michael Davis

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seems like it will work with a few tweaks your parsing is backwards as to what I want to do... I want to parse every row in column1 then every row in column2, you are parsing every column in row1 and so on... I tried with following code for col in range(sheet.ncols): values = [] for row in range(sheet.nrows): values.append(sheet.cell(row, col).value) product[col] = values print product[1] and i get funky result when i print product[1] i get: [u'B',3.0,4.0] I think the value.append only works with ints so its telling me u'B' its a string? – shreddish Jun 12 '13 at 15:04
im sorry for the horrible formatting i cant get it right in this comment box – shreddish Jun 12 '13 at 15:05
1

No, that is working fine. The 'u' at the beginning of the string is just to signify that it is a unicode string. I will add an edit to swap how things are parsed. – Michael Davis Jun 12 '13 at 17:47
My current snippet assumes that you don't want the label value as one of the values in the column info. – Michael Davis Jun 12 '13 at 17:53

Python variable List population

1 Answers1