我正在学习Python中的面向对象编程技术。创建了一个越来越长，越来越复杂的矢量类，我想通过创建一个单独的文件将我的类与主程序分开。随后可以在需要时将该类导入主程序。
这是包含类向量
的文件vector_class.py
class vector(object):
def __init__(self, x=None, y=None, z=None, angle=None):
if angle == None:
self.x, self.y, self.z = x, y, z
if angle != None:
if angle == "rad":
self.r, self.theta, self.phi = x, y, z
if angle == "deg":
self.r = x
self.theta = y * 2. * pi / 360.
self.phi = z * 2. * pi / 360.
self.x = self.r * sin(self.theta) * cos(self.phi)
self.y = self.r * sin(self.theta) * sin(self.phi)
self.z = self.r * cos(self.theta)
def show(self):
print "[", self.x, "\t", self.y, "\t", self.z, "]"
def write(self):
file.write("[" + str(self.x) + ",\t" + str(self.y) + ",\t" + str(self.z) + "]")
def write_sph(self):
file.write("[" + str(self.mag()) + ",\t" + str(self.gettheta()) + ",\t" + str(self.getphi()) + "]")
def swrite(self):
file.write(str(self.x) + "\t" + str(self.y) + "\t" + str(self.z))
def swrite_sph(self):
file.write(str(self.mag()) + "\t" + str(self.gettheta()) + "\t" + str(self.getphi()))
def getx(self):
return self.x
def gety(self):
return self.y
def getz(self):
return self.z
def setx(self, x):
self.x = x
def sety(self, y):
self.y = y
def setz(self, z):
self.z = z
def square(self):
return self.x*self.x + self.y*self.y + self.z*self.z
def mag(self):
return sqrt(self.square())
def gettheta(self):
return arccos(self.z / self.mag())
def getphi(self):
return arctan2(self.y, self.x) # sign depends on which quadrant the coordinates are in
def add(self, v):
v_sum = vector(self.getx() + v.getx(), self.gety() + v.gety(), self.getz() + v.getz())
return v_sum
def minus(self, v):
v_minus = vector(self.getx() - v.getx(), self.gety() - v.gety(), self.getz() - v.getz())
return v_minus
def diff(self, v):
v_diff = vector(abs(self.getx() - v.getx()), abs(self.gety() - v.gety()), abs(self.getz() - v.getz()))
return v_diff
def inc(self, const):
v_new = vector(self.getx() + const, self.gety() + const, self.getz() + const)
return v_new
def times(self, const):
v_new = vector(self.getx() * const, self.gety() * const, self.getz() * const)
return v_new
def div(self, const):
v_new = vector(self.getx() / const, self.gety() / const, self.getz() / const)
return v_new
def sprod(self, v):
ans = self.getx() * v.getx() + self.gety() * v.gety() + self.getz() * v.getz()
return ans
def vprod(self, v):
v_new = vector()
v_new.setx(self.gety() * v.getz() - self.getz() * v.gety())
v_new.sety(self.getz() * v.getx() - self.getx() * v.getz())
v_new.setz(self.getx() * v.gety() - self.gety() * v.getx())
return v_new
这是包含导入类向量
的主程序的文件section2.py
from numpy import *
from vector_class import vector
v0 = vector(0., 0., 0.)
v1 = vector(-1.3054, 7.4033, 2.7362)
v2 = vector(8., 70., 100., "deg")
v3 = vector(8., 1.2217, 1.7453, "rad")
file = open("tasks.txt", 'w')
file.write("task 1 : method to print to file \n\n")
file.write("v0 = ")
v0.write()
file.write("\nv1 = ")
v1.write()
file.write("\n\ntask 2 : spherical polar constructor \n\n")
file.write("v2 = ")
v2.write()
file.write("\nv3 = ")
v3.write()
file.write("\n\ntask 3 : accessing individual coordinates \n\n")
file.write("v1 x component = " + str(v1.getx()) + "\n")
file.write("v1 y component = " + str(v1.gety()) + "\n")
file.write("v1 z component = " + str(v1.getz()) + "\n")
file.write("\ntask 4 : square and magnitude of the three vector \n\n")
file.write("v1 squared = " + str(v1.square()) + "\n")
file.write("v1 magnitude = " + str(v1.mag()) + "\n")
file.write("\ntask 5 : calculating spherical polar angles \n\n")
file.write("v1 spherical = ")
v1.write_sph()
file.write("\nv2 spherical = ")
v2.write_sph()
file.write("\nv3 spherical = ")
v3.write_sph()
file.write("\n\ntask 6 : modifying individual coordinates \n\n")
file.write("v0 = ")
v0.write()
v0.setx(7.77), v0.sety(8.88), v0.setz(9.99)
file.write("\nv0 = ")
v0.write()
file.write("\n\ntask 7 : adding vectors the hard way\n\n")
v4 = vector()
file.write("v0 + v1 = ")
v4.setx(v0.getx() + v1.getx())
v4.sety(v0.gety() + v1.gety())
v4.setz(v0.getz() + v1.getz())
v4.write()
file.write("\n\ntask 8 : overloading the add operator\n\n")
v4 = v0.add(v1)
file.write("v0 + v1 = ")
v4.write()
file.write("\n\ntask 9 : overloading the minus and increment operators \n\n")
v5 = v0.minus(v1)
file.write("v0 - v1 = ")
v5.write()
v6 = v0.inc(3.)
file.write("\nv0 += 3. = ")
v6.write()
file.write("\n\ntask 10 : scaling a vector \n\n")
v7 = v0.times(2.)
file.write("v0 * 2 = ")
v7.write()
v8 = v0.div(2.)
file.write("\nv0 / 2 = ")
v8.write()
file.write("\n\ntask 11 : the scalar product \n\n")
file.write("v0 . v1 = " + str(v0.sprod(v1)))
file.write("\n\ntask 12 : the vector product \n\n")
v9 = v0.vprod(v1)
file.write("v0 x v1 = ")
v9.write()
file.write("\n\ntask13 : triple product test \n\n")
file.write("v0 . (v0 x v1) = " + str(v0.sprod(v0.vprod(v1))))
file.close()
exit()
当我运行主程序时，我收到错误TypeError: descriptor 'write' requires a 'file' object but received a 'str'，但如果所有代码都在一个文件中，一切正常。为什么我会收到错误，如何让类和主程序使用两个单独的文件？
答案 0 :(得分：1)
file是built-in name，因此命名变量file可能会破坏某些内容。 file未在vector.py中定义，因此您正在调用文件对象的write()函数，但您将其称为静态函数，因此它不是＆n ＃39;工作。我同意@roippi关于添加文件对象作为vector构造函数的参数：
def __init__(self, f, x=None, y=None, z=None, angle=None)
我在这里重命名为f以避免我提到的第一个问题，但你可以称之为其他问题。您只需要立即进行查找和替换，替换＆＃34; file＆＃34;用＆＃34; f＆＃34;在vector.py。
答案 1 :(得分：0)
def write(self):
file.write("[" + str(self.x) + ",\t" + str(self.y) + ",\t" + str(self.z) + "]")
您指的是此方法正文中的全局file。全局每个模块，而非整个解释器实例。因此，当事物处于不同的模块中时，python不知道如何解析这个全局名称查找。
我建议重写你的vector构造函数以接收文件句柄（或指向文件的字符串）并将其存储在实例变量中。