如何将矢量场限制在一定半径的圆内？

import math

def limit_vector_field(vector_field, center, radius):
    limited_field = []
    for vector in vector_field:
        distance = math.sqrt((vector[0] - center[0])**2 + (vector[1] - center[1])**2)
        if distance <= radius:
            limited_field.append(vector)
    return limited_field

# 示例用法
vector_field = [(1, 2), (3, 4), (5, 6), (7, 8)]
center = (0, 0)
radius = 5
limited_field = limit_vector_field(vector_field, center, radius)
print(limited_field)