Creating a list from CSV File-CodePudding

I have dataset called "Investor History". I want to create a list from the following dataset using the csv package manually (without using the Panda Dataframe). The dataset has the following 3 headers:

Stock_Price          Exchange_Rate     Invest         
    High                 Low             Y
    High                 High            N       
    Low                  Low             Y

From that dataset, I want to create a list that seems like this as an output:

{('Stock_Price', 'High'), ('Exchange_Rate', 'Low'), ('Invest', 'Y')}
{('Stock_Price', 'High'), ('Exchange_Rate', 'High'), ('Invest', 'N')}
{('Stock_Price', 'Low'), ('Exchange_Rate', 'Low'), ('Invest', 'Y')}

it's more like printing the headers with the elements vertically.

CodePudding user response：

I assume that you have real CSV with data separated by ,

You can use DictReader() to get it as list of dictionares

f = open(filename)

reader = csv.DictReader(f)
rows = list(reader)

[
 {'Stock_Price': 'High', 'Exchange_Rate': 'Low', 'Invest': 'Y'},   
 {'Stock_Price': 'High', 'Exchange_Rate': 'High', 'Invest': 'N'}, 
 {'Stock_Price': 'Low', 'Exchange_Rate': 'Low', 'Invest': 'Y'}
]

And later you can use .items() to convert every dictionary into list of tuples

rows = [list(r.items()) for r in rows]

[
  [('Stock_Price', 'High'), ('Exchange_Rate', 'Low'), ('Invest', 'Y')],
  [('Stock_Price', 'High'), ('Exchange_Rate', 'High'), ('Invest', 'N')],
  [('Stock_Price', 'Low'), ('Exchange_Rate', 'Low'), ('Invest', 'Y')]
]

And if you really want as list of sets then you set() instead of list() - but set() doesn't have to keep order

rows = [set(d.items()) for d in rows]

[
  {('Invest', 'Y'), ('Exchange_Rate', 'Low'), ('Stock_Price', 'High')},   
  {('Exchange_Rate', 'High'), ('Invest', 'N'), ('Stock_Price', 'High')},   
  {('Invest', 'Y'), ('Stock_Price', 'Low'), ('Exchange_Rate', 'Low')}
]

Full working example. I uses io only to simulate file.

import csv
from pprint import pprint

text  ='''Stock_Price,Exchange_Rate,Invest
High,Low,Y
High,High,N
Low,Low,Y'''


import io
f = io.StringIO(text)
#f = open(filename)

reader = csv.DictReader(f)
rows = list(reader)
pprint(rows)

rows1 = [list(d.items()) for d in rows]
pprint(rows1)

rows2 = [set(d.items()) for d in rows]
pprint(rows2)

Result:

[{'Exchange_Rate': 'Low', 'Invest': 'Y', 'Stock_Price': 'High'},
 {'Exchange_Rate': 'High', 'Invest': 'N', 'Stock_Price': 'High'},
 {'Exchange_Rate': 'Low', 'Invest': 'Y', 'Stock_Price': 'Low'}]

[[('Stock_Price', 'High'), ('Exchange_Rate', 'Low'), ('Invest', 'Y')],
 [('Stock_Price', 'High'), ('Exchange_Rate', 'High'), ('Invest', 'N')],
 [('Stock_Price', 'Low'), ('Exchange_Rate', 'Low'), ('Invest', 'Y')]]

[{('Invest', 'Y'), ('Exchange_Rate', 'Low'), ('Stock_Price', 'High')},
 {('Exchange_Rate', 'High'), ('Invest', 'N'), ('Stock_Price', 'High')},
 {('Invest', 'Y'), ('Stock_Price', 'Low'), ('Exchange_Rate', 'Low')}]

CodePudding user response：

Oh, it is simple. Use csv library from Python.