Python返回错误“无法分配给函数调用”

Question

I keep getting the same error.

This is probably a simple mistake, I just haven't coded in a while.

#import
import math

#initailse variables
float(x1)=0.0
float(y1)=0.0
float(x2)=0.0
float(y2)=0.0
float(complete_y)=0.0
float(complete_x)=0.0
float(final_decimal)=0.0
float(heading)=0.0

#get input
print("Welcome user!")
print("please enter your coordinates in format x and y including 
negatives")
x1=input()
y1=input()
print("please enter the coordinates of your target in the format x and y 
including negatives, you can obtain these from the map")
x2=input()
y2=input()
print("please hold for calculation")

#calculate
y2-y1==float(complete_y)
x2-x1==float(complete_x)
y/x==float(final_decimal)
math.asin(a)==float(heading)

#output
print("fire at a heading of", heading, "not including the negative if 
there is one")`enter code here`
print("press enter to close the programme")

Results in an error

expected result is a heading in degrees.

Answer 1

My guess is that you are tying to declare the types before assigning values such as :

float(x)=0.0
x = input()

In python, the type is only known at runtime and you cannot declare type of a variable.

If you do :

x = 0.0
x = input()
print(type(x))

You will see x is a string, because you assigned a string with the input method. If you need a float, you need to convert it.

x = float(input())

As a side note,

#calculate
y2-y1==float(complete_y)

This code is valid if y1 , y2 and complete_y are declared before, it just returns a Boolean, True or False . And do not assign any values.

If you need to assign value, use a single = such as

complete_y = y2 - y1

Answer 2

You can't do

float(x)=0.0

You're calling a function float on a value x and trying to assign 0.0 to the result of that call, which Python doesn't understand. Python knows the type of 0.0 , you don't have to specify that it's a float. Just do

x = 0.0  

Also, I'm not sure what you expect your #calculate section to do, but at the moment it won't have any effect on the rest of the program in any way.