Python - 如何更新 datetime.now()

Question

When I call on datetime.now() in my program it calls the current time, but when I call it again, it displays the previous time. How can I update datetime.now() so it calls the current time eachtime?

Answer 1

You say:

but when I call it again

... but you're NOT calling it again. You're more-than-likely printing/outputting the value of the variable that the first datetime.now() was assigned to.

Let's say you have the following:

from datetime import datetime

first_time = str(datetime.now())
print('First datetime.now() value: %s' % first_time)

You're probably attempting to get the updated time by simply printing first_time (what you incorrectly refer to as "calling" ).

Instead, you should either overwrite first_time by reassigning datetime.now() to it, or you should declare a new variable and assign datetime.now() to it.

# Overwriting & outputting:
# first_time = datetime.now()

# Declaring a new (updated) value (what I'll use in the example):
second_time = datetime.now()

# Outputting:
print('first_time: %s\nsecond_time: %s' % (str(first_time), str(second_time)))

Answer 2

You can define as follows:

def now():
          return datetime.datetime.now().strftime('%d.%m.%Y %H:%M:%S')

use the definition in the following way:

print('{}'.format(now()))