将 CSV 文件导入 Python

Question

我正在尝试将 csv 文件导入 Python。我有两个问题。

Q1.我的代码是：

import csv
with open('highfrequency2.csv') as csvfile:
  freq=csv.reader(csvfile, delimiter=',')
  for row in freq:
    print(row[1],row[8])

但是这里有错误提示

IndexError：列表索引超出范围

Q2.我的数据输出看起来像

['WOSl.TQ', '02-Jan-14', '51:48.0', 'Quote', '', '']
['WOSl.TQ', '02-Jan-14', '51:48.0', 'Quote', '', '']
['WOSl.TQ', '02-Jan-14', '51:48.0', 'Quote', '', '']
['WOSl.TQ', '02-Jan-14', '51:48.0', 'Quote', '', ''] 
['WOSl.TQ', '02-Jan-14', '51:48.0', 'Quote', '', '']
.....
....

我必须使用'r'或'rb'函数来读取文件吗？

我想查看 CSV 文件的第 2 行和第 8 行。

Answer 1

您的行有 6 个元素，您正在尝试打印第 2 个和第 9 个。好吧，后者不存在，因此列表索引超出范围（索引从 0 开始）。

Answer 2

如果您只需要第 2-8 行，请在阅读器对象上使用 itertools.islice：

import csv
from itertools import islice, izip

with open('highfrequency2.csv') as csvfile:
    freq = csv.reader(csvfile)
    # create islice object
    interest = islice(freq, 1, 8, None))
    # iterate over islice object getting row at a time
    for row in interest:
       print(row)

如果您只想要这两个特定行，请使用 6 个 step：

 import csv
from itertools import islice, izip

with open('highfrequency2.csv') as csvfile:
    freq = csv.reader(csvfile)
    interest = islice(freq, 1, 8, 6))
    for row in interest:
       print(row)

或者跳过第一行后在阅读器对象上调用next：

import csv

with open('highfrequency2.csv') as csvfile:
    freq = csv.reader(csvfile)
    next(freq)
    # create generator expression
    interest = (next(freq) for _ in range(7))
    for row in interest:
       print(row)

或者使用枚举：

 import csv

with open('highfrequency2.csv') as csvfile:
    freq = csv.reader(csvfile)
    interest = (row for ind, row in enumerate(freq) if ind in {1,7})
    for row in interest:
       print(row)