Python 我得到的只是“NameError: name 'x' is not defined”错误
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All I get is "NameError: name 'x' is not defined" error
提问by Erik.E
I am new to python and I am trying to make a function that calculates the derivative of another function. So far I have this code
我是 python 的新手，我正在尝试创建一个计算另一个函数的导数的函数。到目前为止我有这个代码
def f(x):
return x**2 + x - 5
def derivative(f,x,h):
return 1/(2*h) * (f(x+h) - f(x-h))
print derivative(f(x),4,6)
but when I try to run it I get "NameError: name 'x' is not defined" error, can someone help me?
但是当我尝试运行它时，我收到“NameError: name 'x' is not defined”错误，有人可以帮助我吗？
回答by IfTrue
When you tell it to :
当你告诉它：
print derivative(f(x),4,6)
you haven't defined the x you are passing as a parameter in f(x).
你还没有定义你在 f(x) 中作为参数传递的 x。
You can do that like so, for example with x = 1 :
你可以这样做，例如 x = 1 ：
def f(x):
return x**2 + x - 5
def derivative(f,x,h):
return 1/(2*h) * (f(x+h) - f(x-h))
x=1
print derivative(f(x),4,6)
回答by ergonaut
x is not defined, and you cannot pass f(x) in the parameter. Try doing something like this:
x 未定义，您不能在参数中传递 f(x)。尝试做这样的事情：
def f(x):
return x**2 + x - 5
def derivative(f,x,h):
return 1/(2*h) * (f(x+h) - f(x-h))
x=12345
print derivative(f,x,6)
回答by Santosh
class Assign:
班级分配：
def _init_(self,x,y):
self.x=x
self.y=y
def sub(self,x,y):
return x-y
num1 = int(input("Enter 1st number: "))
num2 = int(input("Enter 2nd number: "))
obj=Assign()
if x<=0:
print(num1,"-",num2,"=","he's the messiah he's a very naughty boy", obj.sub(num1,num2))
elif x>=0:
print(num1,"-",num2,"=","Yes we all are individuals", obj.sub(num1,num2))
else:
print("invalid input")
