"a = list(a[i] for i in range(0,len(a)))" in python Usage of Generators

 a=[1,2,3,4,5]

k = list(a[x] for x in range(len(a)))

print(k)

a=[1,2,3,4,5]

k = list(a[x] for x in range(len(a)))

print(k)

f = (x for x in a if x%2 == 0) 

print(list(f))

syntax :

variable0 = (variable1 for variable1 in array_name if variable1 % 2 == 0 )

print(variable0)

as above the example inferred single line use of for  loop 

Install Java latest JDK OR JRE IN LINUX WINDOWS

 

Download and Install JDK/JRE 7 in Centos & RHEL

$ su -c "yum install java-1.7.0-openjdk"	# JRE Version
$ su -c "yum install java-1.7.0-openjdk-devel"	# JDK version

Download and Install JDK/JRE 8 in Centos & RHEL

$ su -c "yum install java-1.8.0-openjdk"	# JRE Version
$ su -c "yum install java-1.8.0-openjdk-devel"	# JDK version

Download and Install JDK/JRE 9 in Centos & RHEL

$ su -c "yum install java-1.9.0-openjdk"	# JRE Version
$ su -c "yum install java-1.9.0-openjdk-devel"	# JDK version

Download and Install JDK/JRE 7 in Ubuntu

$ sudo apt-get install openjdk-7-jre		# JRE Version
$ sudo apt-get install openjdk-7-jdk		# JDK version

Download and Install JDK/JRE 8 in Ubuntu

sudo apt-get install openjdk-8-jre		# JRE Version
sudo apt-get install openjdk-8-jdk		# JDK version

Download and Install JDK/JRE 9 in Ubuntu

sudo apt-get install openjdk-9-jre		# JRE Version
sudo apt-get install openjdk-9-jdk		# JDK version

Download and Install JDK/JRE 11 in RHEL/CENTOS

# Install New Version
$ yum install java-11-openjdk-devel

Download and Install JDK/JRE 11 in Ubuntu

---

$ sudo apt-get update
$ sudo apt-get install openjdk-11-jdk -y
$ apt install openjdk-11-jdk-headless -y 

---

Download and Install JDK/JRE 17 in Ubuntu

---

$ sudo apt update
$ sudo apt install openjdk-17-jdk
$ sudo apt install openjdk-17-jre
$ java --version

---

Download and Install JDK/JRE 17 in Centos / RHEL

---

$ sudo yum install java-17-openjdk
$ sudo yum install java-17-openjdk-devel
$ java -version

---

How to Remove Java Installed?

---

# Remove old version
$ java -version
$ yum list installed | grep java
$ yum remove java-1.7.0-openjdk.x86_64
$ yum remove java-1.7.0-openjdk-headless.x86_64
$ yum remove java-1.8.0-openjdk.x86_64
$ yum list installed | grep java
$ yum remove java-1.8.0-openjdk-headless.x86_64
$ java -version

---

How to download Open Java Packages in Linux?

Location - https://openjdk.java.net/install/

Oracle's OpenJDK JDK binaries for Windows, macOS, and Linux are available on release-specific pages of jdk.java.net as .tar.gz or .zip archives.

As an example, the archives for JDK 13 may be found on jdk.java.net/13 and may be extracted on the command line using following depending on the archive type.

$ tar xvf openjdk-13*_bin.tar.gz
or
$ unzip openjdk-13*_bin.zip

How to set JAVA HOME in Linux System?

$ export JAVA_HOME=/opt/jdk1.8.0_144/
$ export PATH=/opt/jdk1.8.0_144/bin:$PATH;

How to set JAVA HOME env in Windows?

---

$ set JAVA_HOME "C:\Program Files\Java\jdk1.8.0"
$ set PATH "%PATH%;%JAVA_HOME%\bin";

$ setx JAVA_HOME "C:\Program Files\Java\jdk1.8.0"
$ setx PATH "%PATH%;%JAVA_HOME%\bin";

---

Command to set default Java version in Linux?

---

$ sudo alternatives --config java

There are 2 programs which provide 'java'.

  Selection    Command
-----------------------------------------------
*+ 1           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.332.b09-1.el7_9.x86_64/jre/bin/java)
   2           java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.15.0.9-2.el7_9.x86_64/bin/java)

Enter to keep the current selection[+], or type selection number: 2
[root@sakri1]# java -version

Also, these commands are helpful
$ sudo update-alternatives --config java
$ sudo update-alternatives --config javac
$ sudo update-alternatives --config java_home

break , continue and pass control flow statements

 when to use 'continue','pass','break' 

when you're using 'for loop, while loop,loops' 

inside for loop you can use 'break,continue,pass' if you're using if-else 

Dunder Methods _ _variable_ _, _ _method_ _, _ _attribute_ _ In Python

In Python, the double underscore prefix and suffix, such as _ _variable_ _,_ _method_ _,

_ _attribute_ _ are often used to denote special or "magic" methods and attributes. These special methods have specific meanings in the context of object-oriented programming and are used to control various behaviors of objects and classes.

Here are some common use cases for double underscore (dunder) methods and attributes in Python:

Dunder Methods (Magic Methods): _ _variable_ _,_ _method_ _,_ _attribute_ _

_ _init_ _: This method is called when an object is created from a class and is used for initialization.

_ _str_ _: Returns a string representation of an object when str() is called on it.

_ _repr_ _: Returns a string representation of an object for debugging and development purposes. It's called when repr() is used.

_ _len_ _: Returns the length of an object when len() is called on it.

_ _getitem_ _ and _ _setitem_ _: These methods are used to define custom behavior for accessing and setting elements in an object, like in dictionaries or lists.

_ _iter_ _ and _ _next_ _: Used to make an object iterable, allowing it to be used in for loops.

_ _enter_ _ and _ _exit_ _: Used in the context of context managers for resource management with the with statement.

Dunder Attributes:

_ _doc_ _: Contains the docstring (documentation) of a class or function.

_ _name_ _: Holds the name of a module, class, or function.

_ _class_ _: Refers to the class of an object.

_ _module_ _: Contains the name of the module in which a class or function is defined.

These double underscore methods and attributes are part of Python's object-oriented programming features and allow you to define how objects of a class should behave when certain built-in functions or operators are used on them. By implementing these methods and attributes in your classes, you can customize the behavior of your objects to better suit your specific needs.