我怎样才能让 time.sleep 更短

Question

My programs supposed to play a game. It's the loading screen I'm having problems with. When I run it, time.sleep acts as if it's sleeping 0.1 seconds, instead of the much smaller numbers I input into it. Why is this? Is there a way I can make the delays shorter? Here's the code:

import os
import random
import time
import sys

def mywrite(line2,line1,t,s,x='small'):
    if x=='small':
        x=0.0000000000000000000000000000000000000000000000000000000000000000000000001
    else:
        x=random.random()*t+s
    word=''
    for c in line1:
        if line1.index(c)<len(line1)-1:
            print(line2)
            word=word+c
            print(word)
            time.sleep(x)
            os.system('cls')
        else:
            print(line2)
            word=word+c
            print(word,' \n')
            time.sleep(x)
mywrite('__________________________________________________________\n',' %33s'%'Scrambled',0.005,0.1,'random')
print('    Press "a" to play %30s'%'Press "s" to exit')
print('__________________________________________________________')
start=input()
if start=='a':
    permission=1
if start=='s':
    permission=0
if permission==0:
    sys.exit()
if permission==1:
    print("Choose Difficulty")
    print('Easy        -Press a')
    print('Hard        -Press b')
    print('Insane      -Press c')
    diff=input()
y=0
while permission==1:
    os.system('cls')
    mywrite('''





  _                       _   _                 
 (_)   ___     __ _    __| | | |  _ __     __ _ 
 | |  / _ \\   / _` |  / _` | | | | '_ \\   / _` |
 | | | (_) | | (_| | | (_| | | | | | | | | (_| |
 |_|  \\___/   \\__, |  \\__,_| |_| |_| |_|  \\__,_|
              |___/                                                       
    ''', 0.005, 0.001)
    time.sleep(2)
    os.system('cls')
    mywrite('''
  _                           _                 
 (_)           __ _          | |           __ _ 
 | |          / _` |         | |          / _` |
 | |         | (_| |         | |         | (_| |
 |_|          \__, |         |_|          \__,_|
              |___/                             
                          _                 
       ___             __| |      _ __  
      / _ \           / _` |     | '_ \ 
     | (_) |         | (_| |     | | | |
      \___/           \__,_|     |_| |_|

    ''', 0.005, 0.001)
    time.sleep(2)
    os.system('cls')
    mywrite('''
  _                           _                 
 | |           __ _          (_)           __ _ 
 | |          / _` |         | |          / _` |
 | |         | (_| |         | |         | (_| |
 |_|          \__,_|         |_|          \__, |
                                          |___/ 
                          _                 
       ___             __| |      _ __  
      / _ \           / _` |     | '_ \ 
     | (_) |         | (_| |     | | | |
      \___/           \__,_|     |_| |_|

    ''', 0.005, 0.001)
    time.sleep(2)
    os.system('cls')
    mywrite('''





  _                       _   _                 
 | |   ___     __ _    __| | (_)  _ __     __ _ 
 | |  / _ \   / _` |  / _` | | | | '_ \   / _` |
 | | | (_) | | (_| | | (_| | | | | | | | | (_| |
 |_|  \___/   \__,_|  \__,_| |_| |_| |_|  \__, |
                                          |___/ 

    ''', 0.005, 0.001)
    time.sleep(4)
    os.system('cls') 
    if y==2:
        break

If that's too long, here's the part that contains the problem:

import os
import random
import time
import sys

def mywrite(line2,line1,t,s,x='small'):
    if x=='small':
        x=0.0000000000000000000000000000000000000000000000000000000000000000000000001
    else:
        x=random.random()*t+s
    word=''
    for c in line1:
        if line1.index(c)<len(line1)-1:
            print(line2)
            word=word+c
            print(word)
            time.sleep(x)
            os.system('cls')
        else:
            print(line2)
            word=word+c
            print(word,' \n')
            time.sleep(x)
while permission==1:
    os.system('cls')
    mywrite('''





  _                       _   _                 
 (_)   ___     __ _    __| | | |  _ __     __ _ 
 | |  / _ \\   / _` |  / _` | | | | '_ \\   / _` |
 | | | (_) | | (_| | | (_| | | | | | | | | (_| |
 |_|  \\___/   \\__, |  \\__,_| |_| |_| |_|  \\__,_|
              |___/                                                       
    ''', 0.005, 0.001)
    time.sleep(2)
    os.system('cls')
    mywrite('''
  _                           _                 
 (_)           __ _          | |           __ _ 
 | |          / _` |         | |          / _` |
 | |         | (_| |         | |         | (_| |
 |_|          \__, |         |_|          \__,_|
              |___/                             
                          _                 
       ___             __| |      _ __  
      / _ \           / _` |     | '_ \ 
     | (_) |         | (_| |     | | | |
      \___/           \__,_|     |_| |_|

    ''', 0.005, 0.001)
    time.sleep(2)
    os.system('cls')
    mywrite('''
  _                           _                 
 | |           __ _          (_)           __ _ 
 | |          / _` |         | |          / _` |
 | |         | (_| |         | |         | (_| |
 |_|          \__,_|         |_|          \__, |
                                          |___/ 
                          _                 
       ___             __| |      _ __  
      / _ \           / _` |     | '_ \ 
     | (_) |         | (_| |     | | | |
      \___/           \__,_|     |_| |_|

    ''', 0.005, 0.001)
    time.sleep(2)
    os.system('cls')
    mywrite('''





  _                       _   _                 
 | |   ___     __ _    __| | (_)  _ __     __ _ 
 | |  / _ \   / _` |  / _` | | | | '_ \   / _` |
 | | | (_) | | (_| | | (_| | | | | | | | | (_| |
 |_|  \___/   \__,_|  \__,_| |_| |_| |_|  \__, |
                                          |___/ 

    ''', 0.005, 0.001)
    time.sleep(4)
    os.system('cls') 
    if y==2:
        break

BTW I'm only a few days into python, so please keep the explanations simple. Thank you.

Answer 1

Actually, time.sleep tries to achieve the desired sleep time but does not guarantee it. From the documentation :

The argument may be a floating point number to indicate a more precise sleep time. The actual suspension time may be less than that requested because any caught signal will terminate the sleep() following execution of that signal's catching routine. Also, the suspension time may be longer than requested by an arbitrary amount because of the scheduling of other activity in the system.

Here are some measurements of accuracy .

There's no cross-platform way to achieve sub-millisecond timing. Eg on windows you cannot get better than 1ms. See https://mail.python.org/pipermail/python-win32/2006-August/004906.html . On Linux, there may be ways using nanosleep(). See also Python: high precision time.sleep

Answer 2

You can test minimum resolution of time.sleep by doing something like:

from datetime import datetime
import time

def test_time(delay):
    start = datetime.now()
    time.sleep(delay)
    finish = datetime.now()
    diff = finish - start
    return diff.total_seconds()

Define that in your REPL (IDLE or terminal or whatever you use) and test it out. On my system, using Python 3.6.1, I get:

>>> test_time(1)
1.014032
>>> test_time(1)
1.014032
>>> test_time(0.1)
0.109204
>>> test_time(0.0001)
0.015601
>>> test_time(0.0002)
0.015601
>>> test_time(0.000000000001)
0.0156
>>> test_time(0.000000000001)
0.0156
>>> test_time(0.0000000000000000000000001)
0.015601
>>>

So the minimum resolution of time.sleep is somewhere around 0.0156 seconds on my machine. Your individual implementation may vary.

Answer 3

i found that if you use:

timer = time.time()
    while timer + wait > time.time(): #wait is your sleep time
      pass

the result is better then when you use:

time.sleep(wait)

but i don't know why