我有一个大约有2000条记录的CSV文件。
每条记录都有一个字符串和一个类别:
This is the first line,Line1
This is the second line,Line2
This is the third line,Line3
我需要把这个文件读入一个列表，看起来像这样:
data = [('This is the first line', 'Line1'),
('This is the second line', 'Line2'),
('This is the third line', 'Line3')]
如何使用Python将此CSV导入到我需要的列表?
当前回答
扩展一下您的需求，假设您不关心行顺序，并希望将它们分组到类别下，下面的解决方案可能适合您:
>>> fname = "lines.txt"
>>> from collections import defaultdict
>>> dct = defaultdict(list)
>>> with open(fname) as f:
... for line in f:
... text, cat = line.rstrip("\n").split(",", 1)
... dct[cat].append(text)
...
>>> dct
defaultdict(<type 'list'>, {' CatA': ['This is the first line', 'This is the another line'], ' CatC': ['This is the third line'], ' CatB': ['This is the second line', 'This is the last line']})
通过这种方式，您可以在类别的键下获得字典中所有可用的相关行。
其他回答
扩展一下您的需求，假设您不关心行顺序，并希望将它们分组到类别下，下面的解决方案可能适合您:
>>> fname = "lines.txt"
>>> from collections import defaultdict
>>> dct = defaultdict(list)
>>> with open(fname) as f:
... for line in f:
... text, cat = line.rstrip("\n").split(",", 1)
... dct[cat].append(text)
...
>>> dct
defaultdict(<type 'list'>, {' CatA': ['This is the first line', 'This is the another line'], ' CatC': ['This is the third line'], ' CatB': ['This is the second line', 'This is the last line']})
通过这种方式，您可以在类别的键下获得字典中所有可用的相关行。
Python3的更新:
import csv
from pprint import pprint
with open('text.csv', newline='') as file:
reader = csv.reader(file)
res = list(map(tuple, reader))
pprint(res)
输出:
[('This is the first line', ' Line1'),
('This is the second line', ' Line2'),
('This is the third line', ' Line3')]
如果csvfile是一个文件对象，它应该用newline= "打开。 csv模块
使用csv模块:
import csv
with open('file.csv', newline='') as f:
reader = csv.reader(f)
data = list(reader)
print(data)
输出:
[['This is the first line', 'Line1'], ['This is the second line', 'Line2'], ['This is the third line', 'Line3']]
如果你需要元组:
import csv
with open('file.csv', newline='') as f:
reader = csv.reader(f)
data = [tuple(row) for row in reader]
print(data)
输出:
[('This is the first line', 'Line1'), ('This is the second line', 'Line2'), ('This is the third line', 'Line3')]
旧的Python 2答案，同样使用csv模块:
import csv
with open('file.csv', 'rb') as f:
reader = csv.reader(f)
your_list = list(reader)
print your_list
# [['This is the first line', 'Line1'],
# ['This is the second line', 'Line2'],
# ['This is the third line', 'Line3']]
这是Python 3中最简单的方法。x导入CSV到多维数组，它只有4行代码，没有导入任何东西!
#pull a CSV into a multidimensional array in 4 lines!
L=[] #Create an empty list for the main array
for line in open('log.txt'): #Open the file and read all the lines
x=line.rstrip() #Strip the \n from each line
L.append(x.split(',')) #Split each line into a list and add it to the
#Multidimensional array
print(L)
一个简单的循环就足够了:
lines = []
with open('test.txt', 'r') as f:
for line in f.readlines():
l,name = line.strip().split(',')
lines.append((l,name))
print lines
