Python 2.7，如果語句被忽略，而不是設置/更改

Question

我當前的if語句不工作，因爲我希望他們，他們應該在某些時候更改變量，但該變量似乎並沒有改變..

import random 
import datetime 
from sched import scheduler 
from time import time, sleep, strftime 

s = scheduler(time, sleep) 
random.seed() 

def run_periodically(start, end, interval, func): 
    event_time = start 
    while event_time < end: 
     s.enterabs(event_time, 0, func,()) 
     event_time += interval + random.randrange(-5, 10) 
    s.run() 

clearscreen = "false" 

def clear(): 
    global clearscreen 
    currenttime = strftime('%H:%M:%S') 
    print currenttime 


## When currenttime is in range, it should change clearscreen from false to true, but it doesn't 
    if currenttime > "00:45:00" and currenttime < "00:46:00": 
     print "Time Range 1 Working" 
     if clearscreen == "false": 
      print "Clear screen is set to false" 
      clearscreen == "true" 

## Same here, when currenttime is in range it should change clearscreen from true to false. 
    if currenttime > "00:46:00" and currenttime < "00:47:00": 
     print "Time Range 2 Working" 
     if clearscreen == "true": 
      print "clearscreen is set to true" 
      clearscreen == "false" 
      print "Cleared Screen" 

getData() 

run_periodically(time()+5, time()+1000000, 10, clear) 

任何人都知道我在做什麼錯，也沒有必要提及使用UTC時間。

感謝 - HYFLEX

Answer 1

clearscreen == "true"有兩個= s不改變clearscreen值。您需要在if塊內寫入clearscreen = "true"（和更晚的clearscreen = "false"）（而不是在if行本身）。