获取第一列CSV文件Python

Question

Trying to get first column (names) into a list to show the user and is then updated with the changes to CSV file. Using this code:

import csv
list = []
exRtFile = open ('exchangeRate.csv','r')
exchReader = csv.reader(exRtFile)
while True:
    for column in exchReader:
        list.append(column and column[0])
        print(list)
        exRtFile.close

However, i get the underired output of:

['US Dollar']
['US Dollar', []]
['US Dollar', [], 'Japanese Yen']
['US Dollar', [], 'Japanese Yen', []]
['US Dollar', [], 'Japanese Yen', [], 'Euro']
['US Dollar', [], 'Japanese Yen', [], 'Euro', []]
['US Dollar', [], 'Japanese Yen', [], 'Euro', [], 'Pound Sterling']
['US Dollar', [], 'Japanese Yen', [], 'Euro', [], 'Pound Sterling', []]
['US Dollar', [], 'Japanese Yen', [], 'Euro', [], 'Pound Sterling', [], 'Japanese Yen']

Answer 1

You are appending the empty column list every other row; test for the column before appending:

col = []
exRtFile = open ('exchangeRate.csv','r')
exchReader = csv.reader(exRtFile)
for column in exchReader:
    if column:
        col.append(column[0])

Do not use an endless loop ( while True: ) in there.

Or using a list comprehension and the file as a context manager to close it automatically:

with open('exchangeRate.csv', newline='') as exRtFile:
    exchReader = csv.reader(exRtFile)
    col = [c[0] for c in exchReader if c]

Note that I added the newline='' argument to the open() call; this is recommended for CSV files because they can use a mix of line endings between values and rows, which the csv.reader() will manage for you if you let it.