相关疑难解决方法(0)

我正在阅读yieldpython中的关键字,并试图了解运行此示例:

def countfrom(n):
    while True:
        print "before yield"
        yield n
        n += 1
        print "after yield"

for i in countfrom(10):
    print "enter for loop"
    if i <= 20:
        print i
    else:
        break

输出是:

before yield
enter for loop
10
after yield
before yield
enter for loop
11
after yield
before yield
enter for loop
12
after yield
before yield
enter for loop
13
after yield
before yield
enter for loop
14
after yield
before yield
enter for loop …