python - 在 python 中使用 if 语句有条件地增加整数计数

Question

假设 if 语句返回 true，我正在尝试增加整数的计数。然而，当这个程序运行时，它总是打印 0。我希望程序第一次运行时 n 增加到 1。第二次到2等等。

我知道函数、类和模块可以使用 global 命令，在它之外，但这不适用于 if 语句。

n = 0
print(n)

if True:
    n += 1

Answer 1

根据上一个答案的评论，你想要这样的东西吗:

n = 0
while True:
    if True: #Replace True with any other condition you like.
        print(n)
        n+=1   

编辑:

Based on the comments by OP on this answer, what he wants is for the data to persist or in more precise words the variable n to persist (Or keep it's new modified value) between multiple runs times.

所以代码如下(假设 Python3.x):

try:
    file = open('count.txt','r')
    n = int(file.read())
    file.close()
except IOError:
    file = open('count.txt','w')
    file.write('1')
    file.close()
    n = 1
print(n)

n += 1

with open('count.txt','w') as file:
    file.write(str(n))
 print("Now the variable n persists and is incremented every time.")
#Do what you want to do further, the value of n will increase every time you run the program

注意: 对象序列化的方法有很多种，上面的例子是最简单的一种，您可以使用专用的对象序列化模块，如 pickle 等。