使用csv.带切片的DictReader

Question

我想知道是否有一种方法可以读取一行中的所有列，除了第一个使用csv作为整型。DictReader，就像这样:

filename = sys.argv[1]
database = []
with open(filename) as file:
reader = csv.DictReader(file)
for row in reader:
row[1:] = int(row[1:])
database.append(row)

我知道这不是一个正确的方法，因为它给出了无法哈希切片的错误。我有一种方法来规避不得不这样做,但是对于未来的参考,我很好奇,是否使用片,我可以有选择地与没有硬编码每一行中的列?

Answer 1

您可以使用key()字典方法来获取每个字典中的键列表和用于进行转换的切片:

import csv
from pprint import pprint
import sys

filename = sys.argv[1]
database = []
with open(filename) as file:
reader = csv.DictReader(file)
for row in reader:
for key in list(row.keys())[1:]:
row[key] = int(row[key])
database.append(row)
pprint(database)

输出:

[{'name': 'John', 'number1': 1, 'number2': 2, 'number3': 3, 'number4': 4},
{'name': 'Alex', 'number1': 4, 'number2': 3, 'number3': 2, 'number4': 1},
{'name': 'James', 'number1': 1, 'number2': 3, 'number3': 2, 'number4': 4}]

Answer 2

使用

import csv
filename = 'test.csv'
database = []
with open(filename) as file:
reader = csv.DictReader(file)
for row in reader:
new_d = {}                                     # Create new dictionary to be appended into database
for i, (k, v) in enumerate(row.items()):       # Loop through items of the row (i = index, k = key, v = value)
new_d[k] = int(v) if i > 0 else v      # If i > 0, add int(v) to the dictionary, else add v
database.append(new_d)                         # Append to database

print(database)

test.csv:

Letter,Num1,Num2
A,123,456
B,789,012
C,345,678
D,901,234
E,567,890

输出:

[{'Letter': 'A', 'Num1': 123, 'Num2': 456},
{'Letter': 'B', 'Num1': 789, 'Num2': 12},
{'Letter': 'C', 'Num1': 345, 'Num2': 678},
{'Letter': 'D', 'Num1': 901, 'Num2': 234},
{'Letter': 'E', 'Num1': 567, 'Num2': 890}]