python变量分配内存

Since, Python is a dynamic programming language so there is no need to declare such type of variable, it automatically declares when first time value assign in it.

由于Python是一种动态编程语言，因此无需声明此类变量，它会在首次分配值时自动声明。

Still, this is a common question asked by many programmers that can we declare any variable without any value?

尽管如此，这是许多程序员提出的一个常见问题， 我们可以声明没有任何值的任何变量吗？

The answer is: "Yes! We can declare such type of variable". To declare a variable without any variable, just assign None.

答案是：“是！我们可以声明这种类型的变量” 。 要声明不带任何变量的变量，只需分配None即可 。

Syntax:

句法：

 variable_name = None

Example:

例：

 num = None

Let’s understand through a program:

让我们通过一个程序来理解：

# Python program to declare a 
# variable without assigning any value 
# declare variable 
num = None
# print the value
print "value of num: ", num
# checking variable
if (num==None):
print "Nothing"
else:	
print "Something"
# assign some value
num = 100
# print the value
print "value of num: ", num
# checking variable
if (num==None):
print "Nothing"
else:	
print "Something"

Output

输出量

    value of num:  None
Nothing
value of num:  100
Something

翻译自: https://www.includehelp.com/python/declare-any-variable-without-assigning-any-value.aspx

python变量分配内存