大约有 40,000 项符合查询结果（耗时：0.0636秒） [XML]
How can I format a decimal to always show 2 decimal places?
...ntize(TWOPLACES, context=Context(traps=[Inexact]))
Traceback (most recent call last):
...
Inexact: None
The next question reads
Q. Once I have valid two place inputs, how do I maintain that invariant throughout an application?
If you need the answer to that (along with lots of other useful inf...
How to drop columns using Rails migration
...ange method that can be reverted* you'll need to inform the data type (and all other field modifiers), so if you rollback that migration, the field can be correctly recreated. * When I say reverted, that's in terms of database structure, of course, data from that column obviously will be lost.
...
OpenSSL and error in reading openssl.conf file
...
You can also set it as part of the computer's environmental variables so all users and services have it available by default. See, for example, Environment variables in Windows NT and How To Manage Environment Variables in Windows XP.
Now you can run openssl commands without having to pass the co...
What is the difference between ~> and >= when specifying rubygem in Gemfile?
... and use that until it reaches a maximum version. So ~>0.8.5 is semantically equivalent to:
gem "cucumber", ">=0.8.5", "<0.9.0"
The easy way to think about it is that you're okay with the last digit incrementing to some arbitrary value, but the ones preceding it in the string cannot be gr...
How does Python 2 compare string and int? Why do lists compare as greater than numbers, and tuples g
...n 2 manual:
CPython implementation detail: Objects of different types except numbers are ordered by their type names; objects of the same types that don’t support proper comparison are ordered by their address.
When you order two strings or two numeric types the ordering is done in the expec...
How do you check in python whether a string contains only numbers?
....isdigit():
From the isdigit documentation:
str.isdigit()
Return True if all characters in the string are digits and there is at least one character, False otherwise. Digits include decimal characters and digits that need special handling, such as the compatibility superscript digits. This covers ...
How to know what the 'errno' means?
When calling execl(...) , I get an errno=2 . What does it mean? How can I know the meaning of this errno ?
15 Answers
...
Instance v state variables in react.js
...nter: function () {
// Open a new one after a delay
this._timeout = setTimeout(function () {
this.openWidget();
}.bind(this), DELAY);
},
handleLeave: function () {
// Clear the timeout for opening the widget
clearTimeout(this._timeout...
What is the difference between 'typedef' and 'using' in C++11?
...
All standard references below refers to N4659: March 2017 post-Kona working draft/C++17 DIS.
Typedef declarations can, whereas alias declarations cannot, be used as initialization statements
But, with the first two non-temp...
Group vs role (Any real difference?)
...effectively inherits those permissions when he acts under that role.
Typically your group membership remains during the duration of your login. A role, on the other hand, can be activated according to specific conditions. If your current role is 'medical-staff' you might be able to see some of the ...