Python for循环不针对i = 1,2进行迭代，仅输出第一次迭代

Question

I am building a for loop using Euler's method for differential equations. The for loop however is not incrementing and only displaying the values for i=0 and not i=1 or i=2.

I have tried manually assigning all arguments and reconstructed the for loop.

import math

def Euler(a,b,N,alpha):
    h=(b-a)/N
    t=a
    w=alpha

    for i in range (0,N):
        w=w+h*(math.exp(t-w))
        t=a+(i*h)
        return t,w    
Euler(0,1,2,1)

I expect the function to return results for i=1 and i=2

Answer 1

As pault mentioned in the comments, your return is inside the loop, which means the function exits on the first iteration.

What you probably want is yield , which would turn the function into a generator:

import math

def Euler(a,b,N,alpha):
    h=(b-a)/N
    t=a
    w=alpha

    for i in range (0,N):
        w=w+h*(math.exp(t-w))
        t=a+(i*h)
        yield t,w

for x, y in Euler(0,1,2,1):
    print(x, y)

>>> 0.0 1.1839397205857212
>>> 0.5 1.3369749844848988

Answer 2

Your return is in the for loop. Unindent return once.