python输入负数_如何让python使用负数

我一直在做一个线性方程计算器，我想知道如何让python使用负数。例如int()、float()等。。。

这是我的密码。import time

print("Hello and welcome to the linear equation calculator.")

time.sleep(2)

print("Enter the first co-ordinate like this - (xx, yy): ")

coordnte1 = input()

print("Now enter the second co-ordinate like this, with the brackets, - (xx,yy): ")

coordnte2 = input()

print("Now the y-intercept: ")

yintrcpt = input()

ydif = coordnte2[1] - coordnte1[1]

xdif = coordnte2[0] - coodrnte1[0]

g = ydif / xdif

print("y = " + g + "x + " + yintrcpt)

问题是：Traceback (most recent call last):

File "C:/Users/Dale/Documents/GitHub/new_python_rpi_experiments/linear.py", line 17, in

ydif = coordnte2[1] - coordnte1[1]

TypeError: unsupported operand type(s) for -: 'str' and 'str'

我对Python很陌生，所以如果有任何帮助，我将不胜感激。