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Extract date (yyyy/mm/dd) from a timestamp in PostgreSQL
...r field representation to a date you can use:
select date(substring('2011/05/26 09:00:00' from 1 for 10));
Test code:
create table test_table (timestamp_field timestamp);
insert into test_table (timestamp_field) values(current_timestamp);
select timestamp_field, date(timestamp_field) from test_t...
Why are these numbers not equal?
...e because some values which are simple, finite decimals (such as 0.1 and 0.05) are not represented exactly in the computer and so the results of arithmetic on them may not give a result that is identical to a direct representation of the "known" answer.
This is a well known limitation of computer a...
Arduino 101 实验05 - 光照传感器，做一个自动小夜灯 · App Inventor 2 中文网
... Arduino 101 实验05 - 光照传感器，做一个自动小夜灯
实验05：光照传感器与自动小夜灯
这个实验做完你会得到什么
一、器材清单
二、接线
...
micro:bit 实验05 - 用 P0 引脚读一个自己接的按钮 · App Inventor 2 中文网
...索 micro:bit 实验05 - 用 P0 引脚读一个自己接的按钮
实验05：用 P0 引脚读一个自己接的按钮
这个实验做完你会得到什么
一、器材清单
二、...
How do I calculate the date in JavaScript three months prior to today?
...edMonth) {
result.setDate(0);
}
return result;
}
var dt2004_05_31 = new Date("2004-05-31 0:00"),
dt2001_05_31 = new Date("2001-05-31 0:00"),
dt2001_03_31 = new Date("2001-03-31 0:00"),
dt2001_02_28 = new Date("2001-02-28 0:00"),
result = addMonths(dt2001_05_31, -2)...
Min/Max of dates in an array?
...
e.g. dates.push('2011/06/05'). Using strings the array can be simply sorted and the first and last member values returned and converted to dates if necessary.
– RobG
Aug 23 '11 at 0:52
...
How to decide font color in white or black depending on background color?
...ove.
The formula given for contrast in the W3C Recommendations is (L1 + 0.05) / (L2 + 0.05), where L1 is the luminance of the lightest color and L2 is the luminance of the darkest on a scale of 0.0-1.0. The luminance of black is 0.0 and white is 1.0, so substituting those values lets you determine ...
How to convert a data frame column to numeric type?
...
David J.
27.4k1818 gold badges105105 silver badges157157 bronze badges
answered Feb 18 '10 at 16:15
JayJay
2,...
乐高 EV3 实验05 - 陀螺仪精确转向 · App Inventor 2 中文网
...索 乐高 EV3 实验05 - 陀螺仪精确转向
实验05：陀螺仪精确转向
这个实验做完你会得到什么
一、器材与接线
二、两种模式
三、界面组...
Regular expression to match non-ASCII characters?
...
var words_in_text = function (text) {
var regex = /([\u0041-\u005A\u0061-\u007A\u00AA\u00B5\u00BA\u00C0-\u00D6\u00D8-\u00F6\u00F8-\u02C1\u02C6-\u02D1\u02E0-\u02E4\u02EC\u02EE\u0370-\u0374\u0376\u0377\u037A-\u037D\u0386\u0388-\u038A\u038C\u038E-\u03A1\u03A3-\u03F5\u03F7-\u0481\u048A-\u052...