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Summarizing multiple columns with dplyr? [duplicate]
...u want to summarize only certain columns, use summarise_at or summarise_if functions.
Alternatively, the purrrlyr package provides the same functionality:
library(purrrlyr)
df %>% slice_rows("grp") %>% dmap(mean)
#> # A tibble: 3 x 5
#> grp a b c d
#> <int>...
How do I grab an INI value within a shell script?
...
echo "$var2"
Bash ini-parser can be found at The Old School DevOps blog site.
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How to create a self-signed certificate with OpenSSL
...ssues (who better to trust than yourself?).
This is probably not the site you are looking for!
The site's security certificate is not trusted!
This is because browsers use a predefined list of trust anchors to validate server certificates. A self-signed certificate does not chain back to a...
Is it possible to define more than one function per file in MATLAB, and access them from outside tha
...hen I was studying for my undergraduate degree in EE, MATLAB required each function to be defined in its own file, even if it was a one-liner.
...
Supabase 拓展：App 接入 Supabase 后端服务（Auth + PostgreSQL + Storage...
...：App 接入 Supabase 后端服务（Auth + PostgreSQL + Storage + Edge Function）
Supabase 拓展
适用场景
组件组成
组件间关系
开发前准备工作
1. 获取 Supabase 配置
2. 配置 Auth 组件
3. 使用功...
How to fix SSL certificate error when running Npm on Windows?
... npm, pip, maven etc. behind a corporate firewall under Windows - it's not fun. I'll try and keep this platform agnostic/aware where possible.
HTTP_PROXY & HTTPS_PROXY
HTTP_PROXY & HTTPS_PROXY are environment variables used by lots of software to know where your proxy is. Under Windows, lo...
How to make connection to Postgres via Node.js
... single user name from id:
db.one('SELECT name FROM users WHERE id = $1', [123])
.then(user => {
console.log(user.name); // print user name;
})
.catch(error => {
console.log(error); // print the error;
});
// alternative - new ES7 syntax with 'await':
// await ...
SqlDataAdapter vs SqlDataReader
...
AdaTheDevAdaTheDev
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App Inventor 2 SQLite 拓展：超流行兼容主流SQL语法的迷你本地数据库引擎 ...
...展由中文网开发及维护，基于开源 aix-SQLite 拓展。
与 TaifunSQLite 功能类似，但TaifunSQLite是收费的，美刀。
.aix 拓展下载：
cn.fun123.SQLite.aix
SQLite
SQLite 是 Android 内置的小型、快速、独立的 SQL（结构化查询语...
Ruby on Rails vs ASP.NET MVC 3 for a .NET Guy? [closed]
...re is any point to consider using RoR over .MVC to develop a real world website?
4 Answers
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