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Official account: Data and intelligence, big data Club The series of articles on big data are presented from three parts: technical ability, business foundation and analytical thinking. You will gain: ❖ improve self-confidence, deal with the interview freely, and get an internship or offer smoothly; ❖ master the basic knowledge of big d ...

Scala process control Branch control if else The if else expression in Scala actually has a return value. The specific return value depends on the last line of the code body that meets the conditions. object TestIfElse { def main(args: Array[String]): Unit = { println("input age") var age = StdIn.readInt() val res :String = if (age < ...

I introduction Use com.com in the work scenario alibaba. Fastjson encountered some time-consuming scenarios. Here are some time-consuming scenarios and simple optimization methods. II Storage form of Jason information The usage scenario is the most basic kv String combination. The loading location is the dirver part of Spark Program. The e ...

17 abstract class and trait Abstract class: Abstract classes are similar to Java, except that there is no attribute abstraction in Java, and scala can have attribute abstraction; Characteristics: The trait can be understood as an upgraded interface in Java In Java, interfaces cannot declare properties without values and methods with implem ...

Scala functions have the principle of simplicity and follow the style of saving what can be saved. This also makes us programmers who come into contact with Scala programming for the first time feel very confused when reading the program. The export is, I don't know what these bars mean. Therefore, the simplification principles of these functio ...

1. Calculation series Please program, calculate and output the sum Sn of the first n items of the following series in the form of script until Sn is just greater than or equal to Q, where q is an integer greater than 0, and its value is input through the keyboard.       For example, if the value of q is 50.0, the output should be: Sn=50.416695 ...

Branch control if else Let the program execute selectively. There are three kinds of branch control: single branch, double branch and multi branch 1. Single branch Basic grammar if (Conditional expression) { Execute code block } Description: when the conditional expression is true, the code of {} will be executed. 2. Double bra ...

pattern matching The pattern matching in scala is similar to the switch syntax in Java, but Scala adds more functions from the syntax, so it is more powerful. Basic grammar In the pattern matching syntax, the match keyword is used to declare, and each branch is declared with the case keyword. When matching is needed, it will start from the f ...

The so-called action operator is the method to trigger job execution reduce Function signature: def reduce (F: (T, t) = > t): t Function Description: aggregate all elements in RDD, first aggregate data in partitions, and then aggregate data between partitions @Test def reduce(): Unit = { val rdd = sc.makeRDD(List(1,2,3,4)) ...

Spark introduction and spark deployment, principle and development environment construction Introduction to spark Spark is a fast, universal and scalable big data analysis and calculation engine based on memory. It is a general memory parallel computing framework developed by the AMP Laboratory (Algorithms, Machines, and People Lab) at the U ...