Ok, this will make more sense. Why does this work:

import csv

with open('test.csv') as csv_file:
    csv_reader = csv.DictReader(csv_file)
    for row in csv_reader:
        print(row)

But this gives an error that the file is closed:

import csv

with open('test.csv') as csv_file:
    csv_reader = csv.DictReader(csv_file)

for row in csv_reader:
    print(row)

Traceback (most recent call last):
File "c:\Users\John\Documents\Python\test_project\test2.py", line 5, in <module> for row in csv_reader: File "C:\Users\John\AppData\Local\Programs\Python\Python311\Lib\csv.py", line 110, in next self.fieldnames File "C:\Users\John\AppData\Local\Programs\Python\Python311\Lib\csv.py", line 97, in fieldnames self._fieldnames = next(self.reader) ^ 
ValueError: I/O operation on closed file.

Does DictReader (and also reader) not just run once and return a value? Why is csv_file being accessed after the line it's used in?

Thanks!