Programmer Group

Advanced knowledge is for developers of packages and class libraries. Functions are only executable code, not objects, closures and functional programming Closure = function + environment variable a=10 def outer(): a=25 def inner(x): print(a*x*x) return inner f=outer() # __Close? Built in variable # enviro ...

First episode: http://www.arppinging.com/wordpress/?p=96 Table operation of oracle rookie learning 1. create table In oracle, create table is used to create a table SQL> create table student(sno number(6),sname varchar2(12),address varchar2(20)); Table created. SQL> desc student; Name Null? Type ...

1. Download Kafka? 2.12-2.0.0.tgz and upload it to / usr/local/kafka / Extract and remove the installation package 2. configuration Modify the config/server.properties of each server cd /usr/local/kafka/kafka_2.12-2.0.0/config vim server.properties Modify several places:broker.id : unique, fill in the number, 10,11,12,13,1 ...

You can draw a line chart into a scatter chart. Scatter diagram can reflect the correlation between two variables, that is, if there is a correlation, is it a positive linear relationship or a negative linear relationship? Even nonlinear? plt.scatter() plt.scatter(x, y, s=20, c=None, marker='o', cmap=No ...

Line chart for economic trend chart, sales fluctuation chart and PV monitoring chart plt.hist() But it seems that we will always use the plt.plot() function to apply plt.hist(x,y,linestyle, linewidth,color,marker, markersize,markeredgecolor, markerfactcolor,label,alpha) X: Specifies the x-axis data of th ...

Simple Hbase paging scheme Most of the paging schemes on the Internet are divided into paging from the server or paging from the client. The paging mode of the server mainly uses the PageFilter filter. First, it is too complex. Secondly, the compatibility of the cluster is not very good. The author gives a simple and easy interm ...

1, demand The output path of MR's map and reduce is the path specified by FileOutPutFormat.setOutPutPath(), but sometimes the code needs to output the results by classification, such as the error information output to one file, and the correct output to another file. In this way, you need to customize to override a FileOutPutFormat class to cla ...

I. significance of Lucene's existence Our usual database search, such as content search, we need to use the like method, which is very inefficient. This is about Lucene. When Lucene searches, it uses an index. This index is similar to the front index table when we look up a dictionary. Compared with looking up a dictionary, we ...

Novice learning, if there are mistakes, please correct, thank you! 1. Start zookeeper and kafka, and set a topic as test fkss. For the convenience of observation, I added it through kafka manager 2. Configure Flume and start it. The listening file is / home / czh / docker-public-file/testplume.log, which is sent to kafka a ...

For the first time, it's a little bit rough to do big data analysis. But fortunately, you can come out with something. Anyway, after you get the data, you can do your own analysis The city with relatively high salary, according to Baidu recruitment information to analyze According to the market demand analysis, the age of ...