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Convert a row of a data frame to vector
...
When you extract a single row from a data frame you get a one-row data frame. Convert it to a numeric vector:
as.numeric(df[1,])
As @Roland suggests, unlist(df[1,]) will convert the one-row data frame to a numeric vector withou...
How to create circle with Bézier curves?
We have a start point (x, y) and a circle radius. There also exists an engine that can create a path from Bézier curve points.
...
搭建高可用mongodb集群（四）—— 分片 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...通过他自己的内部机制就可以搞定！顿时石化了，这么牛X！还是上图看看mongodb通过哪些机制实现路由、分片：
从图中可以看到有四个组件：mongos、config server、shard、replica set。
mongos，数据库集群请求的入口，所有的请求都...
Is the list of Python reserved words and builtins available in a library?
... 'assert', 'break', 'class', 'continue', 'def',
'del', 'elif', 'else', 'except', 'finally', 'for', 'from', 'global', 'if', 'import',
'in', 'is', 'lambda', 'nonlocal', 'not', 'or', 'pass', 'raise', 'return', 'try',
'while', 'with', 'yield']
If you want to include built-in names as well (Pytho...
A variable modified inside a while loop is not remembered
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echo -e $lines | while read line
...
done
The while loop is executed in a subshell. So any changes you do to the variable will not be available once the subshell exits.
Instead you can use a here string to re-write the while loop to be in the main shell process; only echo -e $lines wi...
What are five things you hate about your favorite language? [closed]
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What's is the difference between train, validation and test set, in neural networks?
...e validation data
if the threshold validation accuracy is met
exit training
else
continue training
Once you're finished training, then you run against your testing set and verify that the accuracy is sufficient.
Training Set: this data set is used to adjust the weights on ...
Python __call__ special method practical example
...idators, url validators etc., which broadly fall under the umbrella of RegEx validators. To implement these cleanly, Django resorts to callable classes (instead of functions). It implements default Regex Validation logic in a RegexValidator and then extends these classes for other validations.
clas...
HTTP vs HTTPS performance
...on length
Etc (my personal favorite)
Caching behavior of clients
In my experience, servers that are heavy on dynamic content tend to be impacted less by HTTPS because the time spent encrypting (SSL-overhead) is insignificant compared to content generation time.
Servers that are heavy on serving ...
Use a LIKE statement on SQL Server XML Datatype
... easily:
SELECT *
FROM WebPageContent
WHERE data.value('(/PageContent/Text)[1]', 'varchar(100)') LIKE 'XYZ%'
The .value method gives you the actual value, and you can define that to be returned as a VARCHAR(), which you can then check with a LIKE statement.
Mind you, this isn't going to be awf...