如何接受负值作为 Python 中的输入？

Question

如何接受负值作为输入？

import math
x_coordinates = input("Enter the x coordinates: ")
y_coordinates = input("Enter the y coordinates: ")

x_coordinates = [int(x) for x in x_coordinates]
y_coordinates = [int(x) for x in y_coordinates]

total_x = (x_coordinates[-1] - x_coordinates[0]) ** 2
total_y = (y_coordinates[-1] - y_coordinates[0]) ** 2
total = total_x + total_y
total = math.sqrt(total)
print(total)

谢谢。

Answer 1

我假设您正在输入诸如1 -42 14或类似的输入。 input()返回一个字符串。 当您执行[int(x) for x in x_coordinates]时，您正在对字符串中的每个字符调用int() 。 因此，您应该首先在空格上.split()字符串，然后在每个成员上调用int() ：

x_coordinates = [int(x) for x in x_coordinates.split()]

鉴于上述输入，这将返回

[1, -42, 14]

Answer 2

input给你一个字符串，当你迭代它时，你会分别得到每个字符。 想出一个分隔符，比如空格，然后分割输入：

import math

x_coordinates = input("Enter the x coordinates: ")
y_coordinates = input("Enter the y coordinates: ")

x_coordinates = [int(x) for x in x_coordinates.split(" ")]
y_coordinates = [int(x) for x in y_coordinates.split(" ")]

total_x = (x_coordinates[-1] - x_coordinates[0]) ** 2
total_y = (y_coordinates[-1] - y_coordinates[0]) ** 2
total = total_x + total_y
total = math.sqrt(total)
print(total)

然后：

robert@here:~$ python mcve.py
Enter the x coordinates: 1 2 3
Enter the y coordinates: -1 -2 -3
2.8284271247461903

也就是说，如果您只想读取 2 x 和 2 y 值，您可能应该只使用单独的变量。

import math

x1 = int(input("Enter x1: "))
x2 = int(input("Enter x2: "))
y1 = int(input("Enter y1: "))
y2 = int(input("Enter y1: "))

total_x = (x2 - x1) ** 2
total_y = (y2 - y1) ** 2
total = total_x + total_y
total = math.sqrt(total)
print(total)

或者至少检查输入了多少数字并打印错误。

import math

x_coordinates = input("Enter the x coordinates: ")
y_coordinates = input("Enter the y coordinates: ")

x_coordinates = [int(x) for x in x_coordinates.split(" ")]
y_coordinates = [int(x) for x in y_coordinates.split(" ")]
if len(x_coordinates) > 2 or len(y_coordinates) > 2:
    print("Need 2 x and y coordinates")
else:
    total_x = (x_coordinates[-1] - x_coordinates[0]) ** 2
    total_y = (y_coordinates[-1] - y_coordinates[0]) ** 2
    total = total_x + total_y
    total = math.sqrt(total)
    print(total)