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How to convert C# nullable int to int
...r are all correct; I just wanted to add one more that's slightly cleaner:
v2 = v1 ?? default(int);
Any Nullable<T> is implicitly convertible to its T, PROVIDED that the entire expression being evaluated can never result in a null assignment to a ValueType. So, the null-coalescing operator ?...
How to pretty print XML from Java?
... " xmlns=\"http://www.SDMX.org/resources/SDMXML/schemas/v2_0/message\"\n" +
" xmlns:query=\"http://www.SDMX.org/resources/SDMXML/schemas/v2_0/query\">\n" +
" <Query>\n" +
" <query:...
MediaHelper 媒体助手扩展：从媒体文件提取元数据和专辑封面 · App Inventor 2 中文网
... 各版本对比 App上架指南 入门必读 IoT专题 AI2拓展 Aia Store 关于 关于我们 发布日志 服务条款 搜索 ...
ImageView 扩展：图片查看器扩展，支持缩放、双击缩放和动画缩放 · App In...
... 各版本对比 App上架指南 入门必读 IoT专题 AI2拓展 Aia Store 关于 关于我们 发布日志 服务条款 搜索 ...
Cosine Similarity between 2 Number Lists
...e the nuts-and-bolts implementation:
import math
def cosine_similarity(v1,v2):
"compute cosine similarity of v1 to v2: (v1 dot v2)/{||v1||*||v2||)"
sumxx, sumxy, sumyy = 0, 0, 0
for i in range(len(v1)):
x = v1[i]; y = v2[i]
sumxx += x*x
sumyy += y*y
sumxy...
How to fluently build JSON in Java?
...deBuilder object(@NonNull String k1, String v1, @NonNull String k2, String v2) {
return object(k1, v1).with(k2, v2);
}
public static ObjectNodeBuilder object(@NonNull String k1, String v1, @NonNull String k2, String v2,
@NonNull String k3, String v3) {
return object(k1, v1, k2, v2...
TCPServer TCP服务器扩展：在Android设备上创建TCP服务器 · App Inventor 2 中文网
... 各版本对比 App上架指南 入门必读 IoT专题 AI2拓展 Aia Store 关于 关于我们 发布日志 服务条款 搜索 ...
API Versioning for Rails Routes
...espace :api do
namespace :v1 do
resources :users
end
namespace :v2 do
resources :users
end
match 'v:api/*path', :to => redirect("/api/v2/%{path}")
match '*path', :to => redirect("/api/v2/%{path}")
end
If your mind is still intact after this point, let me explain.
First,...
Finding quaternion representing the rotation from one vector to another
...
Quaternion q;
vector a = crossproduct(v1, v2);
q.xyz = a;
q.w = sqrt((v1.Length ^ 2) * (v2.Length ^ 2)) + dotproduct(v1, v2);
Don't forget to normalize q.
Richard is right about there not being a unique rotation, but the above should give the "shortest arc," which...
For each row return the column name of the largest value
...make examples using sample reproducible):
DF <- data.frame(V1=c(2,8,1),V2=c(7,3,5),V3=c(9,6,4))
colnames(DF)[apply(DF,1,which.max)]
[1] "V3" "V1" "V2"
A faster solution than using apply might be max.col:
colnames(DF)[max.col(DF,ties.method="first")]
#[1] "V3" "V1" "V2"
...where ties.method...