CSV 读取特定行

Question

我有一个包含 100 行的 CSV 文件。

如何读取特定行？

我想读第 9 行或第 23 行等？

Answer 1

您可以使用

list comprehension

来过滤文件，如下所示：

with open('file.csv') as fd:
    reader=csv.reader(fd)
    interestingrows=[row for idx, row in enumerate(reader) if idx in (28,62)]
# now interestingrows contains the 28th and the 62th row after the header

Answer 2

使用

list

一次性抓取所有行作为列表。然后通过列表中的索引/偏移量访问目标行。例如：

#!/usr/bin/env python

import csv

with open('source.csv') as csv_file:
    csv_reader = csv.reader(csv_file)
    rows = list(csv_reader)

    print(rows[8])
    print(rows[22])

Answer 3

您只需跳过必要的行数即可：

with open("test.csv", "rb") as infile:
    r = csv.reader(infile)
    for i in range(8): # count from 0 to 7
        next(r)     # and discard the rows
    row = next(r)   # "row" contains row number 9 now

Answer 4

您可以阅读所有内容，然后使用普通列表来查找它们。

with open('bigfile.csv','rb') as longishfile:
    reader=csv.reader(longishfile)
    rows=[r for r in reader]
print row[9]
print row[88]

如果您有一个巨大的文件，这可能会耗尽您的内存，但如果文件少于 10,000 行，您不应该遇到任何大的速度下降。

Answer 5

你可以这样做：

with open('raw_data.csv') as csvfile:
    readCSV = list(csv.reader(csvfile, delimiter=','))
    row_you_want = readCSV[index_of_row_you_want]

Answer 6

也许这可以帮助你，使用 pandas 你可以轻松地做到这一点

loc

'''
Reading 3rd record using pandas -> (loc)
Note : Index start from 0 
If want to read second record then 3-1 -> 2
loc[2]` -> read second row and `:` -> entire row details 
'''

import pandas as pd
df = pd.read_csv('employee_details.csv')
df.loc[[2],:]

输出：

Answer 7

with open("data.csv") as data_file:
    data = csv.reader(data_file)
    temperature = []
    for row in data:
        print(row[1])

如果您处理的数据量较少，我发现这是一种更简单的方法。