当包含 1 或 2 个其他命名属性时，在 Python 中显示 csv 文件的属性

Question

我是 python 新手，非常感谢您的帮助。我在 Excel 中创建了一个汽车属性文件，并将其另存为 csv 文件，名为 cars.csv，如下所示：

Car make, colour, price, number of seats, automatic, petrol
Ford, black, 40000,5,yes,no
Tesla, white, 90000,4,yes,no

在标题之后，我有 20 行包含不同的汽车及其属性。

有人可以帮助我用 python 代码返回所有具有 4 个座位的汽车品牌，或者说成本 40000，或者说这两个属性吗？谢谢。

Answer 1

您可以使用Pandas：

# pip install pandas
import pandas as pd

df = pd.read_csv('cars.csv', skipinitialspace=True)
print(df)

# Output
  Car make colour  price  number of seats automatic petrol
0     Ford  black  40000                5       yes     no
1    Tesla  white  90000                4       yes     no

过滤您的数据框

out = df[(df['number of seats'] == 4) | (df['price'] == 40000)]
print(out)

# Output
  Car make colour  price  number of seats automatic petrol
0     Ford  black  40000                5       yes     no
1    Tesla  white  90000                4       yes     no

您还可以阅读此

Answer 2

如果您不想使用任何库，可以使用此方法

# The return value of this method can be handled like a list, but its called a generator object
# This method loads all cars from the csv file and yield this data
def load_cars():
    with open('Cars.csv', 'r') as f:
        for counter, line in enumerate(f):
            if counter > 0:# I skipped the header row
                line_content = line.split(", ")
                producer, colour, price, number_of_seats, automatic, petrol = line_content
                yield producer, colour, price, number_of_seats, automatic, petrol # This is like one item in the list

# The statement below is called a list comprehension
# the load_cars method returns the list like object and it iterates over each object, which is put in car
# The car is put in the list if the condition after the if keyword is true
# Each car which fulfills the condition is in the new created list
filtered_cars = [car_data for car_data in load_cars() if car_data[3] == "4" and car_data[2]=="40000"]
filtered_car_names = [car_data[0] for car_data in filtered_cars]

Answer 3

您应该在这里使用 pandas.loc[] 函数。如果使用 pandas 加载 csv，则可以使用 loc 函数仅选择符合条件的行。

import pandas as pd

# if index was dropped when saving the csv
car_atts = pd.read_csv('path to file as string')

# if index was not dropped
car_atts = pd.read_csv('path to file as string', index_col=0)

4_seater_cars = car_atts.loc[car_atts['number of seats'] == 4]

# if col name is type string
fourty_k_cars = car_atts.loc[car_atts['40000'] == True]

# if col name is type int
fourty_k_cars = car_atts.loc[car_atts[40000] == True]

# you can use the & (AND) to find rows that match both conditions
4_seater_fourty_k_cars = car_atts.loc[
    (car_atts['number of seats'] == 4) &
    (car_atts['40000'] == True)
]

# you can use the | (OR) to find rows that match either condition
4_seater_fourty_k_cars = car_atts.loc[
    (car_atts['number of seats'] == 4) |
    (car_atts['40000'] == True)
]

希望这能回答您的问题。

快乐编码！！