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Example: php boolean to string $converted_res = $res ? 'true' : 'false' ;

Example 1: format code intellij // Mac CMD + Option + L // Windows Ctrl + Alt + L Example 2: format code intellij Ctrl + Alt + L

Answer : $true and $false . Those are constants, though. There are no language-level literals for booleans. Depending on where you need them, you can also use anything that coerces to a boolean value, if the type has to be boolean, e.g. in method calls that require boolean (and have no conflicting overload), or conditional statements. Most non-null objects are true, for example. null , empty strings, empty arrays and the number 0 are false. [bool]1 and [bool]0 also works. To add more information to already existing answers : The boolean literals $true and $false also work as is when used as command line parameters for PowerShell (PS) scripts. For the below PS script which is stored in a file named installmyapp.ps1 : param ( [bool]$cleanuprequired ) echo "Batch file starting execution." Now if I've to invoke this PS file from a PS command line, this is how I can do it: installmyapp.ps1 -cleanuprequired $true OR installmyapp.ps1 -cleanuprequir

Example: static variable in c++ /* this example show where and how static variables are used */ # include <iostream> # include <string> //doing "using namespace std" is generally a bad practice, this is an exception using namespace std ; class Player { int health = 200 ; string name = "Name" ; //static keyword static int count = 0 ; public : //constructor Player ( string set_name ) : name { set_name } { count ++ ; } //destructor ~ Player ( ) { count -- ; } int how_many_player_are_there ( ) { return count ; } } ; int main ( ) { Player * a = new Player ( "some name" ) ; cout << "Player count: " << * a . how_many_player_are_there ( ) << std :: endl ; Player * b = new Player ( "some name" ) ; cout << "Player count: " << * a . how_many_player_are_there (

Answer : A helper function for appending DataFrame to existing Excel file: def append_df_to_excel(filename, df, sheet_name='Sheet1', startrow=None, truncate_sheet=False, **to_excel_kwargs): """ Append a DataFrame [df] to existing Excel file [filename] into [sheet_name] Sheet. If [filename] doesn't exist, then this function will create it. Parameters: filename : File path or existing ExcelWriter (Example: '/path/to/file.xlsx') df : dataframe to save to workbook sheet_name : Name of sheet which will contain DataFrame. (default: 'Sheet1') startrow : upper left cell row to dump data frame. Per default (startrow=None) calculate the last row in the existing DF and write to the next row... truncate_sheet : truncate (remove and recreate) [sheet_name] before

Example: 10 min to milliseconds 10 min to milliseconds -> 600000

Answer : Its because the react-router context isn't set in that component. Since its the <Router> component that sets the context you could use useHistory in a sub-component, but not in that one. Note to other people that run into this problem and already have wrapped the component with Router component. Make sure that Router and the useHistory hook are imported from the same package. The same error can be thrown when one of them are imported from react-router and the other one from react-router-dom and the package versions of those packages don't match. Don't use both of them, read about the difference here. useHistory won't work in the component where you have your Routes because the context which is needed for useHistory is not yet set. useHistory will work on any child component or components which your have declared in your Router but it won't work on Router 's parent component or Router component itself.

Example: Abstraction example python from abc import ABC , abstractclassmethod class Parent ( ABC ) : @abstractclassmethod def pqr ( self ) : pass class Child ( Parent ) : def pqr ( self ) : print ( "PQR" ) obj = Child ( ) obj . pqr ( )

Example 1: bootstarp btn colors < button type = "button" class = "btn btn-primary" > Blue < /button > < button type = "button" class = "btn btn-secondary" > Grey < /button > < button type = "button" class = "btn btn-success" > Green < /button > < button type = "button" class = "btn btn-danger" > Red < /button > < button type = "button" class = "btn btn-warning" > Yellow < /button > < button type = "button" class = "btn btn-info" > Ligth blue < /button > < button type = "button" class = "btn btn-light" > White < /button > < button type = "button" class = "btn btn-dark" > Black < /button > < button type = "button" class = "btn btn-link" > White with blue text < /button > Example 2:

Example: react chart js 2 npm install -- save react - chartjs - 2 chart . js

Example 1: bfs traversal of graph in c // BFS algorithm in C # include <stdio.h> # include <stdlib.h> # define SIZE 40 struct queue { int items [ SIZE ] ; int front ; int rear ; } ; struct queue * createQueue ( ) ; void enqueue ( struct queue * q , int ) ; int dequeue ( struct queue * q ) ; void display ( struct queue * q ) ; int isEmpty ( struct queue * q ) ; void printQueue ( struct queue * q ) ; struct node { int vertex ; struct node * next ; } ; struct node * createNode ( int ) ; struct Graph { int numVertices ; struct node * * adjLists ; int * visited ; } ; // BFS algorithm void bfs ( struct Graph * graph , int startVertex ) { struct queue * q = createQueue ( ) ; graph -> visited [ startVertex ] = 1 ; enqueue ( q , startVertex ) ; while ( ! isEmpty ( q ) ) { printQueue ( q ) ; int currentVertex = dequeue ( q ) ; printf ( "Vis

Answer : The 2to3 script replaces execfile(filename, globals, locals) by exec(compile(open(filename, "rb").read(), filename, 'exec'), globals, locals) This seems to be the official recommendation. You may want to use a with block to ensure that the file is promptly closed again: with open(filename, "rb") as source_file: code = compile(source_file.read(), filename, "exec") exec(code, globals, locals) You can omit the globals and locals arguments to execute the file in the current scope, or use exec(code, {}) to use a new temporary dictionary as both the globals and locals dictionary, effectively executing the file in a new temporary scope. execfile(filename) can be replaced with exec(open(filename).read()) which works in all versions of Python Newer versions of Python will warn you that you didn't close that file, so then you can do this is you want to get rid of that warning: with open(filename) as infile:

This is a CMake Environment Variable . Its initial value is taken from the calling process environment. Default compilation flags to be used when compiling CXX (C++) files. Will only be used by CMake on the first configuration to determine CXX default compilation flags, after which the value for CXXFLAGS is stored in the cache as CMAKE_CXX_FLAGS . For any configuration run ( including the first), the environment variable will be ignored if the CMAKE_CXX_FLAGS variable is defined. See also CMAKE_CXX_FLAGS_INIT .

Answer : Update v3.3 Update: Android Studio 3.1 update, some of the icon images have changed. Click this icon in Android Studio. Original: Click this icon in Android Studio for the Android SDK manager And your Android SDK Location will be here Do you have a screen of the content of your folder? This is my setup: I hope these screenshots can help you out. The Android SDK path is usually C:\Users\<username>\AppData\Local\Android\sdk .

Answer : Yes you can index an array, but you have to use the array operators and the GIN-index type. Example: CREATE TABLE "Test"("Column1" int[]); INSERT INTO "Test" VALUES ('{10, 15, 20}'); INSERT INTO "Test" VALUES ('{10, 20, 30}'); CREATE INDEX idx_test on "Test" USING GIN ("Column1"); -- To enforce index usage because we have only 2 records for this test... SET enable_seqscan TO off; EXPLAIN ANALYZE SELECT * FROM "Test" WHERE "Column1" @> ARRAY[20]; Result: Bitmap Heap Scan on "Test" (cost=4.26..8.27 rows=1 width=32) (actual time=0.014..0.015 rows=2 loops=1) Recheck Cond: ("Column1" @> '{20}'::integer[]) -> Bitmap Index Scan on idx_test (cost=0.00..4.26 rows=1 width=0) (actual time=0.009..0.009 rows=2 loops=1) Index Cond: ("Column1" @> '{20}'::integer[]) Total runtime:

Example: how to clear pod cache in react native rm -rf ~/Library/Caches/CocoaPods rm -rf Pods rm -rf ~/Library/Developer/Xcode/DerivedData/* pod deintegrate pod setup pod install