time | 易学教程

How to pause a script just for a fraction of a second in PHP using the SLEEP() function?

阅读更多关于 How to pause a script just for a fraction of a second in PHP using the SLEEP() function?

问题 sleep(1); #waits/sleeps for one second then continue running the script Q1. How to make this 1/100 of a second? which of these work: 0,01 or 0.01 or .01 ? Q2. What are alternatives? wait(); or snap(); ?? how do they differ (more/less precise)? 回答1: Q1. How to make this 1/100 of a second? which of these work: 0,01 or 0.01 or .01 ? None of the above! usleep is what you want for fractions of a second. usleep(100000) will sleep for one tenth of one second. Your other options are time_nanosleep

Changing jpg 'date taken' to be 5 hours before existing value?

阅读更多关于 Changing jpg 'date taken' to be 5 hours before existing value?

问题 I have some photos that were taken in a different timezone from what is needed. I need to convert the existing date taken value to be 5 hours earlier. I have some code below, but I'm unsure how to read each file's 'date taken' attribute and then subtract 5 hours from that. I thought that I could use exif to process this, like below. Im not sure how to know which format the date is stored in, or how to actually write the new date value to the 'date taken' field. import os import glob from exif

Why passing a list as a parameter performs better than passing a generator?

阅读更多关于 Why passing a list as a parameter performs better than passing a generator?

问题 I was making an answer for this question, and when I tested the timing for my solution I came up with a contradiction to what I thought was correct. The guy who made the question wanted to find a way to know how many different lists were contained within another list. (for more information, you can check the question) My answer was basically this function: def how_many_different_lists(lists): s = set(str(list_) for list_ in lists) return len(s) Now, the situation came when I measured the time

python datetime、time、date

阅读更多关于 python datetime、time、date

python datetime Python提供了多个内置模块用于操作日期时间，像calendar，time，datetime。time模块我在之前的文章已经有所介绍，它提供的接口与C标准库time.h基本一致。相比于time模块，datetime模块的接口则更直观、更容易调用。今天就来讲讲datetime模块。 datetime模块定义了两个常量：datetime.MINYEAR和datetime.MAXYEAR，分别表示datetime所能表示的最小、最大年份。其中，MINYEAR = 1，MAXYEAR = 9999。（对于偶等玩家，这个范围已经足够用矣~~） datetime模块定义了下面这几个类： datetime.date：表示日期的类。常用的属性有year, month, day；datetime.time：表示时间的类。常用的属性有hour, minute, second, microsecond；datetime.datetime：表示日期时间。datetime.timedelta：表示时间间隔，即两个时间点之间的长度。datetime.tzinfo：与时区有关的相关信息。（这里不详细充分讨论该类，感兴趣的童鞋可以参考python手册）注：上面这些类型的对象都是不可变（immutable）的。下面详细介绍这些类的使用方式。 date类 date类表示一个日期

Timing Kernel launches in CUDA while using Thrust

阅读更多关于 Timing Kernel launches in CUDA while using Thrust

问题 Kernel launches in CUDA are generally asynchronous, which (as I understand) means that once the CUDA kernel is launched control returns immediately to the CPU. The CPU continues doing some useful work while the GPU is busy number crunching unless the CPU is forcefully stalled using cudaThreadsynchronize() or cudaMemcpy() . Now I have just started using the Thrust library for CUDA. Are the function calls in Thrust synchronous or asynchronous? In other words, if I invoke thrust::sort(D.begin()

How NOHZ=On affects do_timer in linux kernel

阅读更多关于 How NOHZ=On affects do_timer in linux kernel

问题 In a simple experiment I set NOHZ=OFF and used printk to print how often the do_timer function gets called. It gets called every 10 ms on my machine. However if NOHZ=ON then there is a lot of jitter in the way do_timer gets called. Most of the times it does get called every 10 ms but there are times when it completely misses the deadlines. I have researched about both do_timer and NOHZ. do_timer is the function responsible for updating jiffies value and is also responsible for the round robin

How to delete last item in list?

阅读更多关于 How to delete last item in list?

问题 I have this program that calculates the time taken to answer a specific question, and quits out of the while loop when answer is incorrect, but i want to delete the last calculation, so i can call min() and it not be the wrong time, sorry if this is confusing. from time import time q = input('What do you want to type? ') a = ' ' record = [] while a != '': start = time() a = input('Type: ') end = time() v = end-start record.append(v) if a == q: print('Time taken to type name: {:.2f}'.format(v)

How to delete last item in list?

阅读更多关于 How to delete last item in list?

Unity system time for android System.DateTime.now doesn't work? [closed]

阅读更多关于 Unity system time for android System.DateTime.now doesn't work? [closed]

问题 Closed . This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed 3 months ago . I made this code that works fine on the editor but not on my phone. I used unity 2017.4.3. The problem is that when the app is closed in the andriod device, it doesnt feel it at all but it works fine in the editor so why doesn't "System.DateTime.now" doesn't work in the andriod device is is there

Unity system time for android System.DateTime.now doesn't work? [closed]

阅读更多关于 Unity system time for android System.DateTime.now doesn't work? [closed]