Tutorial by Examples: com

In Emacs M-x slime will start slime with the default (first) Common Lisp implementation. If there are multiple implementations provided (via variable slime-lisp-implementations), other implementations can be accessed via M-- M-x slime, which will offer the choice of available implementations in mini...

C++17 namespace a { namespace b { template<class T> struct qualifies : std::false_type {}; } } namespace other { struct bob {}; } namespace a::b { template<> struct qualifies<::other::bob> : std::true_type {}; } You can enter both the a and b n...

Compare two Strings ignoring case: "School".equalsIgnoreCase("school"); // true Don't use text1.toLowerCase().equals(text2.toLowerCase()); Languages have different rules for converting upper and lower case. A 'I' would be converted to 'i' in English. But in Turkish a 'I' ...

You can loop over a Structure or COM collection. <cfset myBooks = StructNew()> <cfset myVariable = StructInsert(myBooks,"ColdFusion","ColdFusion MX Bible")> <cfset myVariable = StructInsert(myBooks,"HTML","HTML Visual QuickStart")> <cf...

List comprehensions are a syntactic construct to create a list based on existing lists. In erlang a list comprehension has the form [Expr || Qualifier1, ..., QualifierN]. Where qualifiers are either generators Pattern <- ListExpr or filter like integer(X) evaluating to either true or false. Th...

If an array happens to have one or more nil elements and these need to be removed, the Array#compact or Array#compact! methods can be used, as below. array = [ 1, nil, 'hello', nil, '5', 33] array.compact # => [ 1, 'hello', '5', 33] #notice that the method returns a new copy of the array w...

Problem In a similar way that SQL injection allows an attacker to execute arbitrary queries on a database, command-line injection allows someone to run untrusted system commands on a web server. With an improperly secured server this would give an attacker complete control over a system. Let's sa...

Arrays can be compared for equality with the aptly named isEqualToArray: method, which returns YES when both arrays have the same number of elements and every pair pass an isEqual: comparison. NSArray *germanMakes = @[@"Mercedes-Benz", @"BMW", @"Porsche", ...

A compound literal is an unnamed object which is created in the scope where is defined. The concept was first introduced in C99 standard. An example for compound literal is Examples from C standard, C11-§6.5.2.5/9: int *p = (int [2]){ 2, 4 }; p is initialized to the address of the first ele...

Comments are used to explain code when the basic code itself isn't clear. Python ignores comments, and so will not execute code in there, or raise syntax errors for plain english sentences. Single-line comments begin with the hash character (#) and are terminated by the end of line. Single lin...

Transact-SQL supports two forms of comment writing. Comments are ignored by the database engine, and are meant for people to read. Comments are preceded by -- and are ignored until a new line is encountered: -- This is a comment SELECT * FROM MyTable -- This is another comment WHERE Id = 1; ...

Notice, that in order to change file prmissions, your device need to be rooted, su binary doesn't come with factory shipped devices! Convention: adb shell su -c "chmod <numeric-permisson> <file>" Numeric permission constructed from user, group and world sections. For exa...

Here's the utility class: public class SharedPreferencesCompat { public static void putStringSet(SharedPreferences.Editor editor, String key, Set<String> values) { if (Build.VERSION.SDK_INT >= 11) { while (true) { try { ...

A component can be registered either globally or locally (bind to another specific component). var Child = Vue.extend({ // ... }) var Parent = Vue.extend({ template: '...', components: { 'my-component': Child } }) Thiw new component () will only be available in...

Passing an object to the data property when registering a component would cause all instances of the component to point to the same data. To solve this, we need to return data from a function. var CustomComponent = Vue.extend({ data: function () { return { a: 1 } } })

add: add the specified files on the next commit addremove: add all new files, delete all missing files backout: reverse effect of earlier changeset commit, ci: commit the specified files or all outstanding changes copy, cp: mark files as copied for the next commit forge...

Functions which return a character vector Base R has two functions for invoking a system command. Both require an additional parameter to capture the output of the system command. system("top -a -b -n 1", intern = TRUE) system2("top", "-a -b -n 1", stdout = TRUE) ...

Interfaces and implementations (types that implement an interface) are "detached". So it is a rightful question how to check at compile-time if a type implements an interface. One way to ask the compiler to check that the type T implements the interface I is by attempting an assignment us...

reduce(_:combine:) can be used in order to combine the elements of a sequence into a single value. It takes an initial value for the result, as well as a closure to apply to each element – which will return the new accumulated value. For example, we can use it to sum an array of numbers: let numbe...

When building a custom release track, it's common to keep packages in the /packages directory as git submodules. The following command allows you to fetch all of the latest commits for the submodules in your /packages directory at the same time. git submodule foreach git pull origin master