Tutorial by Examples: var

requests uses specific environment variables automatically for proxy detection. HTTP_PROXY will define the proxy URL to use for HTTP connections HTTPS_PROXY will define the proxy URL to use for HTTPS connections Once these environment variables are set, the Python code does not need to pass a...

project structure (ansible best practice). project/ group_vars/ development inventory.development playbook.yaml it all starts with inventory.development [development] dev.fakename.io [development:vars] ansible_host: 192.168.0.1 ansible_user: dev ansible_pass: pass ansible...

First, add a reference to <EEPROM.h> at the start of your sketch: #include <EEPROM.h> Then your other code: // Stores value in a particular address in EEPROM. There are almost 512 addresses present. // Store value 24 to Address 0 in EEPROM int addr = 0; int val = 24...

This example deals with one of the most fundamental aspects of the VHDL language: the simulation semantics. It is intended for VHDL beginners and presents a simplified view where many details have been omitted (postponed processes, VHDL Procedural Interface, shared variables...) Readers interest...

To get the actual type for a variable declared using var, call GetSymbolInfo() on the SemanticModel. You can open an existing solution using MSBuildWorkspace, then enumerate its projects and their documents. Use a document to obtain its SyntaxRoot and SemanticModel, then look for VariableDeclaration...

This example shows more detailed build settings: env=Environment( CPPPATH='/usr/include/boost/', CPPDEFINES=['foo'], LIBS=['bar'], SCONS_CXX_STANDARD='c++11') env.Program('hello', Glob('src/*.cpp')) This builds the executable hello from all the cpp files in src, with the f...

To use the value stored in a variable, use the dollar sign followed by the variable name enclosed by parentheses or curly braces. x = hello y = $(x) # y now contains the value "hello" y = ${x} # parentheses and curly braces are treated exactly the same If a variable's name is only ...

Simply-expanded variables behave like variables from traditional programming languages. The expression on the right-hand side is evaluated, and the result is stored in the variable. If the right-hand side contains a variable reference, that variable is expanded before the assignment takes place. ...

When defining a recursively-expanded variable, the contents of the right-hand side are stored as-is. If a variable reference is present, the reference itself is stored (not the value of the variable). Make waits to expand the variable references until the variable is actually used. x = hello y =...

Within the context of an individual rule, Make automatically defines a number of special variables. These variables can have a different value for each rule in a makefile and are designed to make writing rules simpler. These variables can only be used in the recipe portion of a rule. VariableDesc...

The ?= operator is an extension that behaves like =, except that the assignment only occurs if the variable is not already set. x = hello x ?= world # $(x) will yield "hello"

The += operator is a common extension that adds the specified content to the end of the variable, separated by a space. x = hello x += world Variable references in the right-hand side will be expanded if and only if the original variable was defined as a simply-expanded variable.

Project structure project/ group_vars/ development inventory.development playbook.yaml These variables will be applied to hosts under the development group due to the filename. --- ## Application app_name: app app_url: app.io web_url: cdn.io app_friendly: New App env_type: ...

val and var scala> val a = 123 a: Int = 123 scala> a = 456 <console>:8: error: reassignment to val a = 456 scala> var b = 123 b: Int = 123 scala> b = 321 b: Int = 321 val references are unchangeable: like a final variable in Java, once it has been initial...

Variance measures how far a set numbers is spread out from it's mean. From practical perspective it is squared distance from its mean (center) - the bigger the number the farther the point is. The following example would return variance of salary values SELECT name, salary, VARIANCE(salary) "...

I find that the examples in the docker inspect documentation seem magic, but do not explain much. Docker inspect is important because it is the clean way to extract information from a running container docker inspect -f ... container_id (or all running container) docker inspect -f ... $(docker p...

It is suggested that you define groups based on purpose of the host (roles) and also geography or datacenter location (if applicable): File inventory/production [rogue-server] 192.168.1.1 [atlanta-webservers] www-atl-1.example.com www-atl-2.example.com [boston-webservers] www-bos-1.examp...

ggplot(iris[iris$Species == "setosa",],aes(Sepal.Width)) + geom_density() Here, we are subsetting the dataframe before passing it to ggplot. It is a very useful tool derived from the data frame data structure. To make the code more readable, one can also use dplyr's filter: libr...

Server side Meteor.methods({ getData() { return 'Hello, world!'; } }); Client side <template name="someData"> {{#if someData}} <p>{{someData}}</p> {{else}} <p>Loading...</p> {{/if}} </template> Template.someData.on...

Server side Meteor.methods({ getData() { return 'Hello, world!'; } }); Client side <template name="someData"> {{#if someData}} <p>{{someData}}</p> {{else}} <p>Loading...</p> {{/if}} </template> Template.someData.on...