Tutorial by Examples: p

The following will echo each line in the file C:\scripts\testFile.txt. Blank lines will not be processed. for /F "tokens=*" %%A in (C:\scripts\testFile.txt) do ( echo %%A rem do other stuff here ) More advanced example shows, how derived in FOR loop from a restricted files set...

Simple one-liners may be specified as command line arguments to perl using the -e switch (think "execute"): perl -e'print "Hello, World!\n"' Due to Windows quoting rules you can't use single-quoted strings but have to use one of these variants: perl -e"print qq(Hello, W...

perl -ne'print if /foo/' file.txt Case-insensitive: perl -ne'print if /foo/i' file.txt

perl -pe"s/foo/bar/g" file.txt Or in-place: perl -i -pe's/foo/bar/g' file.txt On Windows: perl -i.bak -pe"s/foo/bar/g" file.txt

perl -lane'print "$F[0] $F[-1]"' data.txt # prints the first and the last fields of a space delimited record CSV example: perl -F, -lane'print "$F[0] $F[-1]"' data.csv

perl -ne'print if 5..10' file.txt

Without a backup copy (not supported on Windows) perl -i -pe's/foo/bar/g' file.txt With a backup copy file.txt.bak perl -i.bak -pe's/foo/bar/g' file.txt With a backup copy old_file.txt.orig in the backup subdirectory (provided the latter exists): perl -i'backup/old_*.orig' -pe's/foo/bar/g' ...

It is good practice to test the calling program's __name__ variable before executing your code. import sys def main(): # Your code starts here # Don't forget to provide a return code return 0 if __name__ == "__main__": sys.exit(main()) Using this pattern ens...

Adding components one after another results in a UI that's hard to use, because the components all are somewhere. The components are ordered from top to bottom, each component in a separate "row". To remedy this and provide you as developer with a possibility to layout components easily S...

I always think it is nice to have a very simple, self-contained example so that nothing is assumed when I am learning a new task. This answer is that for deleting UITableView rows. The project performs like this: This project is based on the UITableView example for Swift. Add the Code Create a ...

Weka is a collection of machine learning algorithms for data mining tasks. The algorithms can either be applied directly to a dataset or called from your own Java code. Weka contains tools for data pre-processing, classification, regression, clustering, association rules, and visualization. It is al...

3.0 The => operator has the same precedence as the assignment operator = and is right-associative. It is used to declare lambda expressions and also it is widely used with LINQ Queries: string[] words = { "cherry", "apple", "blueberry" }; int shortestWordLength...

If your application is going to run on different devices, it's going to need to render to different ViewPorts, based on the device size. You can deal with this in two ways: with javascript rules, or CSS media styles. If you've been using a MVC or MVVM library, such as Angular or Ember (or Blaze, for...

Before you compile your app and run it on your device, you'll need create some icons and splash screens, and add a mobile-config.js file to your app. App.icons({ // iOS 'iphone': 'resources/icons/icon-60x60.png', 'iphone_2x': 'resources/icons/[email protected]', 'ipad': 'resources/icons...

Now it's time to go through the Meteor Cordova Phonegap Integration documentation. Since that documentation was written, XCode and Yosemite have been released, which has caused some hiccups in installation. Here are the steps we had to go through to get Meteor compiled to an iOS device. Upgrade ...

Register your Apple Developer Account Register an App ID for your app Register the UUID of your testing devices Generate an iOS App Development provisioning profile Generate a CertificateSigningRequest from KeychainAccess Submit CertificateSigningRequest to https://developer.apple.com/accou...

You'll need to separate out your application layer from your database layer, and that means specifying the MONGO_URL. Which means running your app through the bundle command, uncompressing it, setting environment variables, and then launching the project as a node app. Here's how... #make sure you...

Then go into the mongo shell and initiate the replica set, like so: mongo > rs.initiate() PRIMARY> rs.add("mongo-a") PRIMARY> rs.add("mongo-b") PRIMARY> rs.add("mongo-c") PRIMARY> rs.setReadPref('secondaryPreferred')

The replica set will need an oplog user to access the database. mongo PRIMARY> use admin PRIMARY> db.addUser({user:"oplogger",pwd:"YOUR_PASSWORD",roles:[],otherDBRoles:{local:["read"]}}); PRIMARY> show users

Your upstart script will need to be modified to use multiple IP addresses of the replica set. start on started mountall stop on shutdown respawn respawn limit 99 5 script # our example assumes you're using a replica set and/or oplog integreation export MONGO_URL='mongodb://mongo-a...