Tutorial by Examples: ha

Assuming we have the following function: function foo(tab) return tab.a end -- Script execution errors out w/ a stacktrace when tab is not a table Let's improve it a bit function foo(tab) if type(tab) ~= "table" then error("Argument 1 is not a table!", 2) end ...

Format: cd "<path>" Example: cd "C:\Program Files (x86)\Microsoft Office" cd is an abbreviation for chdir and the two commands behave in the exact same way. For the sake of consistency, cd will be used throughout this topic. To navigate to the directory one leve...

In C++, looping through a sequence container c can be done using indexes as follows: for(size_t i = 0; i < c.size(); ++i) c[i] = 0; While simple, such writings are subject to common semantic errors, like wrong comparison operator, or wrong indexing variable: for(size_t i = 0; i <= c.size(...

First, add the following permissions to the manifest of your project in order to enable device storage access: <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /> ...

If the response has already been created and set on the response object outside the regular rendering process (e.g., in an observer), the 'no-renderLayout' flag can be set on the action controller using Mage::app()->getFrontController()->getAction()->setFlag('','no-renderLayout'); ...

Before proceeding, it is recommended to have a brief idea about Adjacency Matrix and BFS Dijkstra's algorithm is known as single-source shortest path algorithm. It is used for finding the shortest paths between nodes in a graph, which may represent, for example, road networks. It was conceived by E...

Bosun notifications are assigned to alert definitions using warnNotification and critNotification and indicate where to send the rendered alert template when a new incident occur. The ${env.VARIABLENAME} syntax can be used to load values from an Environmental Variable. In order to post alerts to Hi...

In some cases you may want to change which notification you use based on a tag in the Alert keys. You can do this using the Lookup feature. Note: Lookup only works if you are using OpenTSDB and sending data to the Bosun to be indexed. For other backends or non-indexed data you have to use lookupSeri...

Note that the allowDiskUse: true option is optional but will help mitigate out of memory issues as this aggregation can be a memory intensive operation if your collection size is large - so i recommend to always use it. var duplicates = []; db.transactions.aggregate([ { $group: { _id: { c...

Consider the dataframes left and right left = pd.DataFrame([['a', 1], ['b', 2]], list('XY'), list('AB')) left A B X a 1 Y b 2 right = pd.DataFrame([['a', 3], ['b', 4]], list('XY'), list('AC')) right A C X a 3 Y b 4 join Think of join as wanting to combine to dat...

When some programmers see this advice: "Testing strings using == is incorrect (unless the strings are interned)" their initial reaction is to intern strings so that they can use ==. (After all == is faster than calling String.equals(...), isn't it.) This is the wrong approach, from...

Regular expression support for tust is provided by the regex crate, add it to your Cargo.toml: [dependencies] regex = "0.1" The main interface of the regex crate is regex::Regex: extern crate regex; use regex::Regex; fn main() { //"r" stands for "raw" str...

If you want to perform a user input validation of your textfield use the following code snippet: // MARK: - UITextFieldDelegate let allowedCharacters = CharacterSet(charactersIn:"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvxyz").inverted func textField(_ textField:...

Before reading this example, it is required to have a brief idea on edge-relaxation. You can learn it from here Bellman-Ford Algorithm is computes the shortest paths from a single source vertex to all of the other vertices in a weighted digraph. Even though it is slower than Dijkstra's Algorithm, i...

Floyd-Warshall's algorithm is for finding shortest paths in a weighted graph with positive or negative edge weights. A single execution of the algorithm will find the lengths (summed weights) of the shortest paths between all pair of vertices. With a little variation, it can print the shortest path ...

After the record gets stored in the database, we want to inspect what was changed on the record. We'll do this inspection by comparing values between the old and new record instances. // 1.0, Revealing Module pattern var myNamespace = myNamespace || {}; myNamespace.example = (function () { ...

// 1.0 // Utilize the type argument and raw Strings to filter your // execution by the action function beforeLoad(type, form, request) { // Don't do anything on APPROVE // Note that `type` is an Object, so we must use ==, not === if (type == "approve") { return...

In SuiteScript 1.0, we retrieve the current execution context using nlapiGetContext().getExecutionContext(), then we compare the result to the appropriate raw Strings. // 1.0 in Revealing Module pattern var myNamespace = myNamespace || {}; myNamespace.example = (function () { var exports =...

In most text editors, the standard shortcut for saving the current document is Ctrl+S (or Cmd+S on macOS). Vim doesn't have this feature by default but this can be mapped to make things easier. Adding the following lines in .vimrc file will do the job. nnoremap <c-s> :w<CR> inoremap &...

Using the PhantomData type like this allows you to use a specific type without needing it to be part of the Struct. use std::marker::PhantomData; struct Authenticator<T: GetInstance> { _marker: PhantomData<*const T>, // Using `*const T` indicates that we do not own a T } imp...