Python 循环辅助答案

【问题标题】：Python Loop AssistancePython 循环辅助
【发布时间】：2019-11-13 06:42:26
【问题描述】：

我是 Python 新手，需要帮助解决一些循环问题。

我有一个名为 test1.csv 的 CSV 文件，其中有两列（Fruit 和 Fruit_Container）

import csv

def fruits():
    with open('test1.csv', mode='r') as csv_file:
        csv_reader = csv.DictReader(csv_file)
        for row in csv_reader:
            print(f'Fruits: {row["Fruit"]}')

def fruit_container():
    with open('test1.csv', mode='r') as csv_file:
        csv_reader = csv.DictReader(csv_file)
        for row in csv_reader:
            print(f'The fruits are: {row["Fruit"]} and they are placed in a {row["Fruit_Container"]}')

fruits()
fruit_container()

我得到的结果如下：

Fruits: Apple
Fruits: Banana
Fruits: Orange
The fruits are: Apple and they are placed in a Crate
The fruits are: Banana and they are placed in a Crate
The fruits are: Orange and they are placed in a Crate

但我想要的结果如下：

Fruits: Apple
Fruits: Banana
Fruits: Orange

The fruits are: 
Apple and they are placed in a Crate
Banana and they are placed in a Crate
Orange and they are placed in a Crate

我怎样才能实现这个输出？

问候丹尼斯

【问题讨论】：

将“The fruits are:”（只有那些词！）的打印移动到循环之前，它只会打印一次。
在fruit_container() 函数中，“水果是：”应该在循环之外

标签： python loops csv

【解决方案1】：

你需要在for循环之外写The fruits are:：

def fruit_container():
    with open('test1.csv', mode='r') as csv_file:
        csv_reader = csv.DictReader(csv_file)
        print("The fruits are: ")
        for row in csv_reader:
            print(f'{row["Fruit"]} and they are placed in a {row["Fruit_Container"]}')

【讨论】：

【解决方案2】：

您可以使用以下代码来达到预期的效果：

定义：

import csv
def fruits():
    with open('test1.csv', mode='r') as csv_file:
        csv_reader = csv.DictReader(csv_file)
        fruits_list = []
        fruits_container_list = []
        for row in csv_reader:
            fruits_list.append(row["Fruit"])
            fruits_container_list.append(row["Fruits_Container"])
        return fruits_list, fruits_container_list

方法调用：

fruits_list, fruits_container_list  = fruits()
for index in range(0, len(fruits_list)):
        print('Fruits: {}'.format(fruits_list[index]))  
print('\nThe fruits are: ')
for index in range(0, len(fruits_list)):
        print('{} and they are placed in a {}'.format(fruits_list[index], fruits_container_list[index]))

return fruits_list 和return fruits_container_list 是调用的两个列表对象的返回语句。这有助于简化流程。 for index in range(0, len(fruits_list)) 遍历列表以生成同步输出。快乐编码！

【讨论】：