从CSV文件创建字典

Question

我正在尝试编写一个python脚本,它将从CSV文件中获取输入,然后将其推送到字典格式(我使用的是Python 3.x).

我使用下面的代码读取CSV文件并且有效:

import csv

reader = csv.reader(open('C:\\Users\\Chris\\Desktop\\test.csv'), delimiter=',', quotechar='|')

for row in reader:
    print(', '.join(row))

但现在我想将结果放入字典中.我希望将CSV文件的第一行用作字典的"键"字段,CSV文件中的后续行填写数据部分.

样本数据:

     Date        First Name     Last Name     Score
12/28/2012 15:15        John          Smith        20
12/29/2012 15:15        Alex          Jones        38
12/30/2012 15:15      Michael       Carpenter      25

我还想对这段代码做些什么,但是现在只需要让字典工作就是我要找的东西.

谁能帮我这个？

编辑版本2:

import csv
reader = csv.DictReader(open('C:\\Users\\Chris\\Desktop\\test.csv'))

result = {}

for row in reader:
    for column, value in row.items():
        result.setdefault(column, []).append(value)
        print('Column -> ', column, '\nValue -> ', value)
print(result)

fieldnames = result.keys()

csvwriter = csv.DictWriter(open('C:\\Users\\Chris\\Desktop\\test_out.csv', 'w'), delimiter=',', fieldnames=result.keys())

csvwriter.writerow(dict((fn,fn) for fn in fieldnames))

for row in result.items():
    print('Values -> ', row)
    #csvwriter.writerow(row)

'''
Test output

'''
test_array = []
test_array.append({'fruit': 'apple', 'quantity': 5, 'color': 'red'});
test_array.append({'fruit': 'pear', 'quantity': 8, 'color': 'green'});
test_array.append({'fruit': 'banana', 'quantity': 3, 'color': 'yellow'});
test_array.append({'fruit': 'orange', 'quantity': 11, 'color': 'orange'});
fieldnames = ['fruit', 'quantity', 'color']
test_file = open('C:\\Users\\Chris\\Desktop\\test_out.csv','w')
csvwriter = csv.DictWriter(test_file, delimiter=',', fieldnames=fieldnames)
csvwriter.writerow(dict((fn,fn) for fn in fieldnames))
for row in test_array:
    print(row)
    csvwriter.writerow(row)
test_file.close()

Answer 1

创建一个字典,然后迭代结果并填充字典中的行.请注意,如果遇到具有重复日期的行,则必须决定要执行的操作(引发异常,替换上一行,丢弃后一行等等)

这是test.csv:

Date,Foo,Bar
123,456,789
abc,def,ghi

和相应的程序:

import csv
reader = csv.reader(open('test.csv'))

result = {}
for row in reader:
    key = row[0]
    if key in result:
        # implement your duplicate row handling here
        pass
    result[key] = row[1:]
print(result)

收益率:

{'Date': ['Foo', 'Bar'], '123': ['456', '789'], 'abc': ['def', 'ghi']}

或者,使用DictReader:

import csv
reader = csv.DictReader(open('test.csv'))

result = {}
for row in reader:
    key = row.pop('Date')
    if key in result:
        # implement your duplicate row handling here
        pass
    result[key] = row
print(result)

结果是:

{'123': {'Foo': '456', 'Bar': '789'}, 'abc': {'Foo': 'def', 'Bar': 'ghi'}}

或者您可能希望将列标题映射到该列的值列表:

import csv
reader = csv.DictReader(open('test.csv'))

result = {}
for row in reader:
    for column, value in row.iteritems():
        result.setdefault(column, []).append(value)
print(result)

产量:

{'Date': ['123', 'abc'], 'Foo': ['456', 'def'], 'Bar': ['789', 'ghi']}

Answer 2

你需要一个Python DictReader类.可以从这里找到更多帮助

import csv

with open('file_name.csv', 'rt') as f:
    reader = csv.DictReader(f)
    for row in reader:
        print row