time

问题 Consider the following code which attempts to get a DateTime that's equivalent to the local time "midnight yesterday": DateTime midnightYesterday = DateTime.Today.AddDays(-1.0d); Will this always result in a DateTime with a time component of 00:00:00 -- regardless of any corner cases such as leap days, leap seconds, or what the local time zone is? More generally: Does calling DateTime.AddDays , passing a whole number as a parameter, always result in a DateTime being returned that has the

问题 In most cases,we convert numeric time to posixct format using R. However, sometimes, we want to compare which time point is earlier, then we would prefer the numeric time format. Thus, it's quite practical question to convert time format to numeric. For example,I have the data format like "2001-03-13 10:31:00", begin <- "2001-03-13 10:31:00" Using R, I want to figure out how to covert it into a numeric, e.g. the Julian time, something like the passing seconds between 1970-01-01 00:00:00 and

问题 This structure is a 64-bit value representing the number of 100-nanosecond intervals since January 1, 1601. Reference: http://msdn.microsoft.com/en-us/library/aa915351 Why it is set "since 1601"? Why not unix time 1970 or even 2000? What can I do with the compatibility of so distant in time dates? Answering to myself. The ANSI Date defines January 1, 1601 as day 1, and is used as the origin of COBOL integer dates. This epoch is the beginning of the previous 400-year cycle of leap years in the

问题 This structure is a 64-bit value representing the number of 100-nanosecond intervals since January 1, 1601. Reference: http://msdn.microsoft.com/en-us/library/aa915351 Why it is set "since 1601"? Why not unix time 1970 or even 2000? What can I do with the compatibility of so distant in time dates? Answering to myself. The ANSI Date defines January 1, 1601 as day 1, and is used as the origin of COBOL integer dates. This epoch is the beginning of the previous 400-year cycle of leap years in the

问题 I am building my first ReactNative iOS and Android app. I am an iOS coder with Swift and Obj-C. How do I fetch the current date using ReactNative. Shall I use Native Modules or is there an ReactNative API from which I can get this data ? 回答1: The JavaScript runtime in React Native has access to date information just like any other environment. As such, simply: new Date() ... will give you the current date. Here's the MDN on working with dates in JS. If you want a good JS library to make

问题 I am building my first ReactNative iOS and Android app. I am an iOS coder with Swift and Obj-C. How do I fetch the current date using ReactNative. Shall I use Native Modules or is there an ReactNative API from which I can get this data ? 回答1: The JavaScript runtime in React Native has access to date information just like any other environment. As such, simply: new Date() ... will give you the current date. Here's the MDN on working with dates in JS. If you want a good JS library to make

问题 I am building my first ReactNative iOS and Android app. I am an iOS coder with Swift and Obj-C. How do I fetch the current date using ReactNative. Shall I use Native Modules or is there an ReactNative API from which I can get this data ? 回答1: The JavaScript runtime in React Native has access to date information just like any other environment. As such, simply: new Date() ... will give you the current date. Here's the MDN on working with dates in JS. If you want a good JS library to make

问题 I am generating tokens for users in PHP when they register. I am wondering if two users could ever get the same token... as this will break the system. Please let me know if this is suffiecient. $token = md5(rand().time()); edit: i am now using a generate_uuid() function i found on another question. will this work? function generate_uuid() { return sprintf( '%04x%04x-%04x-%04x-%04x-%04x%04x%04x', mt_rand( 0, 0xffff ), mt_rand( 0, 0xffff ), mt_rand( 0, 0xffff ), mt_rand( 0, 0x0C2f ) | 0x4000,

问题 I am generating tokens for users in PHP when they register. I am wondering if two users could ever get the same token... as this will break the system. Please let me know if this is suffiecient. $token = md5(rand().time()); edit: i am now using a generate_uuid() function i found on another question. will this work? function generate_uuid() { return sprintf( '%04x%04x-%04x-%04x-%04x-%04x%04x%04x', mt_rand( 0, 0xffff ), mt_rand( 0, 0xffff ), mt_rand( 0, 0xffff ), mt_rand( 0, 0x0C2f ) | 0x4000,

问题 I am using Python 3.6.0 on Windows 10 x64. I just found that in time.ctime(seconds) , seconds parameter has an implicit maximum value, which is 32536799999, almost equals to 2^34.92135 . Is that the maximum value? The error message just says it's an invalid number. >>> import time >>> time.ctime(32536799999) >>> 'Mon Jan 19 15:59:59 3001' >>> time.ctime(32536799999+1) Traceback (most recent call last): File "<stdin>", line 1, in <module> OSError: [Errno 22] Invalid argument I googled and