Tutorial by Examples: nd

NSString *testString = @"There are 42 sheep and 8672 cows."; NSError *error = nil; NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"(\\d+)" options:NSRegularExpressionCaseIns...

The bisect command helps you to track down the changeset that introduced a bug. Reset the bisect state and mark the current revision as bad (it contains the bug!) hg bisect --reset hg bisect --bad Go back to a point where you think the bug isn't present hg update -r -200 Now...

Python 2.x2.7 In Python 2 filter, map and zip built-in functions return a sequence. map and zip always return a list while with filter the return type depends on the type of given parameter: >>> s = filter(lambda x: x.isalpha(), 'a1b2c3') >>> s 'abc' >>> s = map(lambd...

Lubridate provides ymd() series of functions for parsing character strings into dates. The letters y, m, and d correspond to the year, month, and day elements of a date-time. mdy("07-21-2016") # Returns Date ## [1] "2016-07-21" mdy("07-21-2016", t...

date <- now() date ## "2016-07-22 03:42:35 IST" year(date) ## 2016 minute(date) ## 42 wday(date, label = T, abbr = T) # [1] Fri # Levels: Sun < Mon < Tues < Wed < Thurs < Fri < Sat day(date) <- 31 ## "2016-07-31 03:42:35 IST" # If an ...

Intervals are simplest way of recording timespans in lubridate. An interval is a span of time that occurs between two specific instants. # create interval by substracting two instants today_start <- ymd_hms("2016-07-22 12-00-00", tz="IST") today_start ## [1] "2016-07-...

now_dt <- ymd_hms(now(), tz="IST") now_dt ## [1] "2016-07-22 13:53:09 IST" round_date() takes a date-time object and rounds it to the nearest integer value of the specified time unit. round_date(now_dt, "minute") ## [1] "2016-07-22 13:53:00 IST" r...

Unlike durations, periods can be used to accurately model clock times without knowing when events such as leap seconds, leap days, and DST changes occur. start_2012 <- ymd_hms("2012-01-01 12:00:00") ## [1] "2012-01-01 12:00:00 UTC" # period() considers leap year calculati...

GROUP BY is used in combination with aggregation functions. Consider the following table: orderIduserIdstoreNameorderValueorderDate143Store A2520-03-2016257Store B5022-03-2016343Store A3025-03-2016482Store C1026-03-2016521Store A4529-03-2016 The query below uses GROUP BY to perform aggregated calc...

Creating a hub A quick configuration for a hub and node setup in selenium grid. For more information see: Grid 2 docs Requirements To set up a grid hub you need the flowing: Selenium-server-standalone-.jar Creating the hub To Create a Hub you need to run the selenium server. Download Se...

In CSS3, we can stack multiple background in the same element. #mydiv { background-image: url(img_1.png), /* top image */ url(img_2.png), /* middle image */ url(img_3.png); /* bottom image */ background-position: right bottom, ...

The Android specific implementation is a bit more complex because it forces you to inherit from a native Java.Lang.Object and forces you to implement the IOnInitListener interface. Android requires you to provide a valid Android context for a lot of the SDK methods it exposes. Xamarin.Forms exposes ...

' Sometimes we don't need to evaluate all the conditions in an if statement's boolean check. ' Let's suppose we have a list of strings: Dim MyCollection as List(Of String) = New List(of String)() ' We want to evaluate the first value inside our list: If MyCollection.Count > 0 And MyCo...

Yes, you need to SETKEY pre 1.9.6 In the past (pre 1.9.6), your data.table was sped up by setting columns as keys to the table, particularly for large tables. [See intro vignette page 5 of September 2015 version, where speed of search was 544 times better.] You may find older code making use of t...

CREATE UNIQUE INDEX idx_license_id ON Person(DrivingLicenseID) WHERE DrivingLicenseID IS NOT NULL GO This schema allows for a 0..1 relationship - people can have zero or one driving licenses and each license can only belong to one person

It is now a best-practice to use Vector instead of List because the implementations have better performance Performance characteristics can be found here. Vector can be used wherever List is used. List creation List[Int]() // Declares an empty list of type Int List.empty[Int] // U...

The Scala compiler prefixes every argument in the parameter list by default with val. This means that, by default, case classes are immutable. Each parameter is given an accessor method, but there are no mutator methods. For example: case class Foo(i: Int) val fooInstance = Foo(1) val j = fooIn...

Apply will be used when when table valued function in the right expression. create a Department table to hold information about departments. Then create an Employee table which hold information about the employees. Please note, each employee belongs to a department, hence the Employee table has ref...

In normal mode, we can increment the nearest number on the line at or after the cursor with <C-a> and decrement it with <C-x>. In the following examples, the cursor position is indicated by ^. Incrementing and decrementing numbers for i in range(11): ^ <C-x> decrements ...

The Math.random() function should give random numbers that have a standard deviation approaching 0. When picking from a deck of card, or simulating a dice roll this is what we want. But in most situations this is unrealistic. In the real world the randomness tends to gather around an common normal...