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Apache Spark: map vs mapPartitions?
...lize(List("dog", "salmon", "salmon", "rat", "elephant"), 3)
val b = a.map(_.length)
val c = a.zip(b)
c.collect
res0: Array[(String, Int)] = Array((dog,3), (salmon,6), (salmon,6), (rat,3), (elephant,8))
mapPartitions
This is a specialized map that is called only once for each partition.
...
Sort JavaScript object by key
...
@Phil_1984_ This answer and top voted answer are very different. OP's question was how to sort an object literal. Top voted answer says you can't, then gives a workaround by storing sorted keys in an array, then iterating and prin...
Very simple log4j2 XML configuration file using Console and File appender
...gt;
<Appenders>
<Console name="Console" target="SYSTEM_OUT">
<PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n" />
</Console>
<File name="MyFile" fileName="all.log" immediateFlush="false" append="false">
...
Equation (expression) parser with precedence?
...is four function calculator:
http://www.gnu.org/software/bison/manual/html_node/Infix-Calc.html
Look at the generated code, and see that this is not as easy as it sounds. Also, the advantages of using a tool like Bison are 1) you learn something (especially if you read the Dragon book and learn ab...
How does a public key verify a signature?
...autl -encrypt -inkey public.pem -pubin -in message.txt -out message_enc_pub.ssl
openssl rsautl -decrypt -inkey private.pem -in message_enc_pub.ssl -out message_pub.txt
xxd message_enc_pub.ssl # Print the binary contents of the encrypted message
cat message_pub.txt # Print the decrypted...
What is the “N+1 selects problem” in ORM (Object-Relational Mapping)?
...may be correct. How is that possible? See en.wikipedia.org/wiki/Anecdotal_evidence, and also my comment in the other answer to this question.
– whitneyland
Jul 4 '12 at 18:27
7
...
Servlet returns “HTTP Status 404 The requested resource (/servlet) is not available”
...tp://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0"
>
<!-- Config here. -->
</web-app>
Or, in case you're not on Servlet 3.0+ yet (e.g. Tomcat 6 or older), then remove the @WebServlet annotation.
package com.example;
public cl...
Adding the “Clear” Button to an iPhone UITextField
...
func clear_btn(box_is : UITextField){
box_is.clearButtonMode = .always
if let clearButton = box_is.value(forKey: "_clearButton") as? UIButton {
let templateImage = clearButton.imageView?.image?.withRenderingMode(.alway...
What does cmd /C mean? [closed]
...here's also a command to "pause" the cmd window after output: "cmd /c file_name & PAUSE" it is bit different from cmd /k
– Gourav
Sep 5 '15 at 19:34
...
What resources exist for Database performance-tuning? [closed]
...tabase, this guide may also help.
http://download.oracle.com/docs/cd/B28359_01/server.111/b28274/toc.htm
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