从csv文件创建字典?

I am trying to create a dictionary from a csv file. The first column of the csv file contains unique keys and the second column contains values. Each row of the csv file represents a unique key, value pair within the dictionary. I tried to use the csv.DictReader and csv.DictWriter classes, but I could only figure out how to generate a new dictionary for each row. I want one dictionary. Here is the code I am trying to use:

我正在尝试从csv文件创建字典。csv文件的第一列包含唯一的键，第二列包含值。csv文件的每一行表示字典中的唯一键值对。我尝试使用csv。DictReader和csv。DictWriter类，但我只知道如何为每一行生成一个新字典。我想要一本字典。下面是我正在尝试使用的代码:

import csv

with open('coors.csv', mode='r') as infile:
    reader = csv.reader(infile)
    with open('coors_new.csv', mode='w') as outfile:
    writer = csv.writer(outfile)
    for rows in reader:
        k = rows[0]
        v = rows[1]
        mydict = {k:v for k, v in rows}
    print(mydict)

When I run the above code I get a ValueError: too many values to unpack (expected 2). How do I create one dictionary from a csv file? Thanks.

当我运行上面的代码时，我得到一个ValueError:太多的值需要解压(期望2)。如何从csv文件创建一个字典?谢谢。

10 个解决方案

#1

I believe the syntax you were looking for is as follows:

我想您要寻找的语法如下:

with open('coors.csv', mode='r') as infile:
    reader = csv.reader(infile)
    with open('coors_new.csv', mode='w') as outfile:
        writer = csv.writer(outfile)
        mydict = {rows[0]:rows[1] for rows in reader}

Alternately, for python <= 2.7.1, you want:

另外，对于python <= 2.7.1，您需要:

mydict = dict((rows[0],rows[1]) for rows in reader)

#2

import csv
reader = csv.reader(open('filename.csv', 'r'))
d = {}
for row in reader:
   k, v = row
   d[k] = v

#3

Open the file by calling open and then csv.DictReader.

通过调用Open打开文件，然后调用csv.DictReader来打开文件。

input_file = csv.DictReader(open("coors.csv"))

You may iterate over the rows of the csv file dict reader object by iterating over input_file.

您可以通过迭代input_file来遍历csv文件dict reader对象的行。

for row in input_file:
    print row

OR To access first line only

或者只能访问第一行

dictobj = csv.DictReader(open('coors.csv')).next() 

#4

You have to just convert csv.reader to dict:

你只需要转换csv。读者对dict:

~ >> cat > 1.csv
key1, value1
key2, value2
key2, value22
key3, value3

~ >> cat > d.py
import csv
with open('1.csv') as f:
    d = dict(filter(None, csv.reader(f)))

print(d)

~ >> python d.py
{'key3': ' value3', 'key2': ' value22', 'key1': ' value1'}

#5

You can also use numpy for this.

你也可以使用numpy。

from numpy import loadtxt
key_value = loadtxt("filename.csv", delimiter=",")
mydict = { k:v for k,v in key_value }

#6

This isn't elegant but a one line solution using pandas.

这不是优雅的，而是使用熊猫的单线解决方案。

import pandas as pd
pd.read_csv('coors.csv', header=None, index_col=0, squeeze=True).to_dict()

If you want to specify dtype for your index (it can't be specified in read_csv if you use the index_col argument because of a bug):

如果您想为索引指定dtype(如果由于错误而使用index_col参数，则不能在read_csv中指定dtype):

import pandas as pd
pd.read_csv('coors.csv', header=None, dtype={0: str}).set_index(0).squeeze().to_dict()

#7

I'd suggest adding if rows in case there is an empty line at the end of the file

如果文件末尾有空行，我建议添加if行

import csv
with open('coors.csv', mode='r') as infile:
    reader = csv.reader(infile)
    with open('coors_new.csv', mode='w') as outfile:
        writer = csv.writer(outfile)
        mydict = dict(row[:2] for row in reader if row)

#8

If you are OK with using the numpy package, then you can do something like the following:

如果您对使用numpy包没有问题，那么您可以做以下事情:

import numpy as np

lines = np.genfromtxt("coors.csv", delimiter=",", dtype=None)
my_dict = dict()
for i in range(len(lines)):
   my_dict[lines[i][0]] = lines[i][1]

#9

You can use this, it is pretty cool:

你可以用这个，很酷:

import dataconverters.commas as commas
filename = 'test.csv'
with open(filename) as f:
      records, metadata = commas.parse(f)
      for row in records:
            print 'this is row in dictionary:'+rowenter code here

#10

One-liner solution

一行程序解决方案

import pandas as pd

dict = {row[0] : row[1] for _, row in pd.read_csv("file.csv").iterrows()}