Question

我是Python的新手，我想只打印一个巨大的csv文件的前10行。

到目前为止，我的代码打印了csv文件中的所有行

import csv
with open('titanic.csv') as csvfile:
    reader = csv.DictReader(csvfile)
    for row in reader:
        print(row['survived'], row['pclass'], row['name'], row['sex'], row['age'])

Answer 1

使用itertools.islice：

import csv
from itertools import islice

with open('titanic.csv') as csvfile:
    reader = csv.DictReader(csvfile)
    for row in islice(reader, 10): # first 10 only
        print(row['survived'], row['pclass'], row['name'], row['sex'], row['age'])

在您了解情况时，您还可以使用operator.itemgetter使列更容易：

import csv
from itertools import islice
from operator import itemgetter

get_columns = itemgetter('survived', 'pclass', 'name', 'sex', 'age')

with open('titanic.csv') as csvfile:
    reader = csv.DictReader(csvfile)
    for row in islice(reader, 10): # first 10 only
        print(*get_columns(row))

Answer 2

你可以在10行之后break。

import csv
with open('titanic.csv') as csvfile:
    reader = csv.DictReader(csvfile)
    for i,row in enumerate(reader):
        print(row['survived'], row['pclass'], row['name'], row['sex'], row['age'])
        if(i >= 9):
            break

Answer 3

Adrien El Zein的回答足以满足您的提问。但是，如果您认为它有点令人困惑（我不这么认为）：

import csv
counter = 0

with open('titanic.csv') as csvfile:
    reader = csv.DictReader(csvfile)
    for row in enumerate(reader):
       print(row['survived'], row['pclass'], row['name'], row['sex'], row['age'])
       counter += 1
       if counter >= 9:
           break

我所做的就是将变量i重命名为counter。另外，对于替代循环：

import csv
counter = 0

with open('titanic.csv') as csvfile:
    reader = csv.DictReader(csvfile)
    for row in enumerate(reader):
       print(row['survived'], row['pclass'], row['name'], row['sex'], row['age'])
       while counter < 10:
           counter += 1
       else:
           break

我尝试使用Python 3.4.3测试while-else循环（不确定您拥有哪个版本）并且可以告诉您它正常工作。

Answer 4

要从csv文件中获取前N行，请选择字段

#for python 3
import csv
from operator import itemgetter
N=11 # to get 10 rows need use 10+1=11
fname='titanic.csv'
get_columns=itemgetter('survived', 'pclass', 'name', 'sex', 'age')

with open(fname,'r') as csvfile:
    reader = csv.DictReader(csvfile.readlines()[0:N])
    [print(*get_columns(row)) for row in reader]

     # or for all fields : use [print(row)) for row in reader]

如何使用Python仅打印csv文件中的前10行？

4 个答案: