Open .csv file with Python throws NameError

Question

I'm following an example in a book and receiving an error. I have two files. One is named nobel_winners.csv and the other test.py I am trying to open nobel_winners.csv from test.py.

The contents of nobel_winners.csv is:

nobel_winners = [
 {'category': 'Physics',
  'name': 'Albert Einstein',
  'nationality': 'Swiss',
  'sex': 'male',
  'year': 1921},
 {'category': 'Physics',
  'name': 'Paul Dirac',
  'nationality': 'British',
  'sex': 'male',
  'year': 1933},
 {'category': 'Chemistry',
  'name': 'Marie Curie',
  'nationality': 'Polish',
  'sex': 'female',
  'year': 1911}
]

from my test.py, I'm using f = open('nobel_winners.csv', 'w') then cols = nobel_winners[0].keys(). The program then throws:

NameError: name 'nobel_winners' is not defined.

What is going awry here?

Answer 1

I think that's because the variable 'nobel_winners' is not defined before you call it.

I'm not aware with your code but if you are reading from csv, the code below works for me. This my not be the best way though. I did it with some guidance from a question posted here in this site.

def read_from_csv(filename,nrows,ncols):
csv_data = np.zeros((nrows,ncols))

with open(filename,'rb') as csvfile:
  read_csv = csv.reader(csvfile)
  i=0
  for row in read_csv:
      csv_data[i] = np.array(row)
      csv_data[i] = csv_data[i].astype(np.float)
      i += 1
csvfile.close()
return csv_data