Python 如何允许用户输入年数并从该列表中提取平均、最小和最大预期寿命

因此，对于一项任务，我必须允许用户输入一年，python将遍历整个.csv文件（我将链接该文件，以防它允许人们提供更好的帮助），找到该年内所有国家的预期寿命，然后将它们全部加起来，并显示平均值、最小值、，我一直在我的电脑上尝试不同的东西，但对于我的一生来说，我不知道该怎么做，甚至连想都会伤到我的头。如果有人能提供帮助，我将不胜感激。以下是我目前掌握的代码：

filename = 'Life_expectancy.csv'
rows = []
with open(filename) as le_file: 
    next(le_file) 
    for line in le_file: 
 
        line = line.strip().split(",") 
        rows.append(line)

ages = [row[3] for row in rows]
min_age_idx = ages.index(min(ages))
max_age_idx = ages.index(max(ages))


details = rows[min_age_idx]
detailsElectricBoogaloo = rows[max_age_idx]
print('Name: {}, Code: {}, Year: {}, Life Expectancy: {}'.format(details[0], details[1], details[2], details[3]))
print('Name: {}, Code: {}, Year: {}, Life Expectancy:{}'.format(detailsElectricBoogaloo[0], detailsElectricBoogaloo[1], detailsElectricBoogaloo[2], detailsElectricBoogaloo[3]))

我还发现我无法链接文件，所以我将复制并粘贴csv数据的一部分

Entity,Code,Year,Life expectancy (years)
Afghanistan,AFG,1950,27.638
Afghanistan,AFG,1951,27.878
Afghanistan,AFG,1952,28.361
Afghanistan,AFG,1953,28.852
Afghanistan,AFG,1954,29.35
Afghanistan,AFG,1955,29.854
Albania,ALB,1950,54.191
Albania,ALB,1951,54.399
Albania,ALB,1952,54.875
Albania,ALB,1953,55.468
Albania,ALB,1954,56.18
Albania,ALB,1955,57.007
Algeria,DZA,1950,42.087
Algeria,DZA,1951,42.282
Algeria,DZA,1952,42.677
Algeria,DZA,1953,43.081
Algeria,DZA,1954,43.494
Algeria,DZA,1955,43.916

---

世界上每一个数据公开的国家的名单都是这样的，时间在1950年到2019年之间，有些国家在1923年到2019年之间，还有一些国家在这个时间段左右。我甚至想不起如何开始这项工作。

您可以查看pandas DataFrame，您可以在csv中轻松读取该数据框，然后根据您需要的年份进行筛选。

我建议使用csv内置模块解析您的csv，例如

import csv

with open('Life_expectancy.csv', 'r') as file_handler:
    data = [row for row in csv.reader(file_handler)]

但就如何过滤而言，您可以通过多种方式进行过滤：

for循环

results = []

for row in data:

    if row[2] == 'input_year':  # row[2] = third row, zero indexed

        results.append(row)

print(results)

滤器

results = [row for row in filter(lambda x: x[2] == 'input_year', data)]
print(results)

列表理解

results = [row for row in data if row[2] == 'input_year']
print(results)

然后是平均过程：

total_life_expectancy = sum([row[3] for row in results])
average_life_expectancy = total_life_expectancy / len(total_life_expectancy)

---

您甚至可以将这些功能组合到一个步骤中，并将其与上述功能组合在一起，但我建议您分步骤进行操作，以便更轻松地跟踪流程。

您可以使用内置模块

统计信息

，这是一个功能。要查找最小值和最大值，可以使用

min（）/max（）

函数

例如：

import csv
from statistics import mean

data = []
with open('data.csv', 'r', newline='') as f_in:
    csv_reader = csv.reader(f_in, delimiter=',', quotechar='"')
    next(csv_reader)  # skip headers
    for row in csv_reader:
        data.append(row)

year = input('Please enter the year: ')

average = mean(float(d[3]) for d in data if d[2] == year)
min_ = min((d for d in data if d[2] == year), key=lambda k: float(k[3]))
max_ = max((d for d in data if d[2] == year), key=lambda k: float(k[3]))

print('Statistics for year:', year)
print('-' * 80)
print('Average {:.2f}'.format(average))
print('Min :', min_)
print('Max :', max_)

Please enter the year: 1951
Statistics for year: 1951
--------------------------------------------------------------------------------
Average 41.52
Min : ['Afghanistan', 'AFG', '1951', '27.878']
Max : ['Albania', 'ALB', '1951', '54.399']

打印（例如）：

---

我已经重命名了CSV文件

data.CSV

，并且我已经硬编码了

年份

，但是您知道了：

def main():
    import csv
    import statistics

    with open("data.csv") as file:
        reader = csv.DictReader(file)
        year = "1955"
        year_ages = list(map(lambda d: float(d["Life expectancy (years)"]), filter(lambda d: d["Year"] == year, reader)))

    minimum = min(year_ages)
    maximum = max(year_ages)
    average = statistics.mean(year_ages)

    print(year.center(32, "-"))
    print(f"The minimum life expectancy was {minimum:.2f} years.")
    print(f"The maximum life expectancy was {maximum:.2f} years.")
    print(f"The average life expectancy was {average:.2f} years.")

if __name__ == "__main__":
    main()

输出：

--------------1955--------------
The minimum life expectancy was 29.85 years.
The maximum life expectancy was 57.01 years.
The average life expectancy was 43.59 years.
>>> 

---

欢迎来到SO。这不是一个讨论论坛或教程。请花点时间阅读和阅读该页面上的其他链接。花些时间练习这些例子。它将让您了解Python提供的帮助您解决问题的工具。-<代码>如果有人能提供帮助-。这不是答案。谢谢你的帮助，非常有用