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Check if UIColor is dark or bright?
...o use is ((Red value * 299) + (Green value * 587) + (Blue value * 114)) / 1000.
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dplyr summarise: Equivalent of “.drop=FALSE” to keep groups with zero length in output
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Since dplyr 0.8 group_by gained the .drop argument that does just what you asked for:
df = data.frame(a=rep(1:3,4), b=rep(1:2,6))
df$b = factor(df$b, levels=1:3)
df %>%
group_by(b, .drop=FALSE) %>%
summarise(count_a=length(a)...
Validate decimal numbers in JavaScript - IsNumeric()
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2908
@Joel's answer is pretty close, but it will fail in the following cases:
// Whitespace strings...
一分钟读懂低功耗蓝牙(BLE) MTU交换数据包 - 创客硬件开发 - 清泛IT社区，...
...一个较小的值作为以后的MTU，比如说，主设备发出一个150个字节的MTU请求，但是从设备回应MTU是23字节，那么今后双方要以较小的值23字节作为以后的MTU），主从双方约定每次在做数据传输时不超过这个最大数据单元。
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Format number to 2 decimal places
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You want to use the TRUNCATE command.
https://dev.mysql.com/doc/refman/8.0/en/mathematical-functions.html#function_truncate
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Common MySQL fields and their appropriate data types
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answered Dec 10 '08 at 0:57
da5idda5id
8,83288 gold badges3636 silver badges5050 bronze badges
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What is __gxx_personality_v0 for?
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edited Aug 20 '17 at 18:58
curiousguy
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Logical operators for boolean indexing in Pandas
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When you say
(a['x']==1) and (a['y']==10)
You are implicitly asking Python to convert (a['x']==1) and (a['y']==10) to boolean values.
NumPy arrays (of length greater than 1) and Pandas objects such as Series do not have a boolean value -- in other words, they ...
Sass - Converting Hex to RGBa for background opacity
...e, this would work just fine:
@mixin background-opacity($color, $opacity: 0.3) {
background: $color; /* The Fallback */
background: rgba($color, $opacity);
}
element {
@include background-opacity(#333, 0.5);
}
If you ever need to break the hex color into RGB components, though, you ...
Google Maps: how to get country, state/province/region, city given a lat/long value?
...ld look like:
http://maps.googleapis.com/maps/api/geocode/json?latlng=40.714224,-73.961452&sensor=false
Response:
{
"status": "OK",
"results": [ {
"types": [ "street_address" ],
"formatted_address": "275-291 Bedford Ave, Brooklyn, NY 11211, USA",
"address_components": [ {
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