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Why covariance and contravariance do not support value type
IEnumerable<T> is co-variant but it does not support value type, just only reference type. The below simple code is compiled successfully:
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Counting DISTINCT over multiple columns
Is there a better way of doing a query like this:
19 Answers
19
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href=“tel:” and mobile numbers
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When dialing a number within the country you are in, you still need to dial the national trunk number before the rest of the number. For example, in Australia one would dial:
0 - trunk prefix
2 - Area code for New South Wales
6555 - STD...
Docker - how can I copy a file from an image to a host?
...ainers to hosts; I have a Dockerfile that fetches dependencies, compiles a build artifact from source, and runs an executable. I also want to copy the build artifact (in my case it's a .zip produced by sbt dist in '../target/`, but I think this question also applies to jars, binaries, etc.
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驯服Linux OOM Killer（优质英文资料翻译） - 操作系统(内核) - 清泛网移动...
...数量的进程（如果可能限制为一个）的基础上确定的）。badness 分数是使用进程的原始内存大小、它的 CPU 时间 (utime + stime)、运行时间 (uptime - start time) 和它的oom_adj值来计算的。进程使用的内存越多，分数就越高。进程在系统中...
System.Data.SQLite Close() not releasing database file
I'm having a problem closing my database before an attempt to delete the file. The code is just
17 Answers
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Big-O summary for Java Collections Framework implementations? [closed]
I may be teaching a "Java crash-course" soon. While it is probably safe to assume that the audience members will know Big-O notation, it is probably not safe to assume that they will know what the order of the various operations on various collection implementations is.
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Plot correlation matrix into a graph
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Quick, dirty, and in the ballpark:
library(lattice)
#Build the horizontal and vertical axis information
hor <- c("214", "215", "216", "224", "211", "212", "213", "223", "226", "225")
ver <- paste("DM1-", hor, sep="")
#Build the fake correlat...
What does this symbol mean in JavaScript?
This is a collection of questions that come up every now and then about syntax in JavaScript. This is also a Community Wiki, so everyone is invited to participate in maintaining this list.
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javascript set a variable if undefined
I know that I can test for a javascript variable and then define it if it is undefined, but is there not some way of saying
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