Python Tutorial Chapter 2 - More Python

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Python Tutorial Chapter 2 - More Python - MrGeek - 05-17-2013

Chapter -- > 2 :~# More python

#2.1 --|Numbers|--

Python is just like powerful language such as C and java, supports 3 data types for scientific calculations. The three DATA TYPES are :

1. Integer
2. String
3. Boolean

+================================================================+

#2.2 --|Variables|--

In python language, Variables needn't declared.
You can call them right from where you need them!

For instance
Variable can be assigned by just simply typing x = 6
But in other lanugages such as C++
You have to declare variable as follows;

Quote:int x;

Another example

Quote:>>>x = 3
>>>y = 3
>>>print(x*y)
9

First variable x is assgined integer 3
Then variable y is assgined integer 3
After that, print function is used to output the results.
Now you should have grub the basics of variable Biggrin

+===============================================================+

2.3# --|Functions|-- (General)

Now we're going to talk about functions briefly
Functions are vital in every programming lanugages.
You can define your own function or use the existing function.
Function is sort of like a feature, for example "pow(x,y)" is a function.
Functions can help make your program more powerful and as well as making your program easier to maintain!

In C++ when writing functions (I lost memory on C++ not very sure Biggrin

)

Quote:1. Definition must be first declared
2. Write the definition
3. Call the Defininition
are bound to be followed.

+==================================================================+

2.4# --|Modules|-- (General)

You may have realized the import statement above some of the programs.
Eg. import math
Import is a command that import the modules into the program.
Modules can make program more powerful.
We'll come to modules later...

+==================================================================+

2.5# --|Comments|--

If you have tried any one of programming language, you would have heard about comment definately. Every programming language has it's own style of writting comments.
For example, For eg. C style comment is /* comment */
In python you just need to use sharp sign "#"

Code:
#!usr/bin/env python

#This is a comment

Print('hello')

#This is a comment again

Interpreter will not execute the string/code after # sign, it knows that it's a comment, and simply skips. Commenting makes the program more readable and easier to debug.
We'll go into details about writing functions in next chapter.

Commonly used Functions
1.print()
2.input() / raw_input()
2.float
3.complex

Example, 1, 2, 3, 4 are integers.
Python do not have long integer type as C language. It's included in integer type.
This might be a weakness.

6.39 and 787.6E-9 is float data type.
787.6E-9 = 787.6*10-9

It also supports complex number that are commonly used in Mathematics.
Example 9+7j

Now we'll deal with number operatoin. #OpNo Biggrin

Open up Python shell. Let's get started.

Code:
>>> 1+1

2

>>>1/2

0

Now why 1 divided by 2 didn't result in 0.5?
Because Python took it as integer. But it's not the problem anymore in python version 3.

Code:
>>>1.0/2.0

0.5

In this way, we can calcualte basic Arithmetic Operations, such as addition, subtruction, multiplication, and division.
“+ - / *”
Another one

Code:
>>>1%2

"%" operator is used to calculate remainder of a division.

Code:
>>>3**2

9

"**" means power

Code:
>>>-3**2

-9

>>>(-3)**2

9

Latest version didn't have the buffer overflow anymore!
Hexadecimal and Octal are also supported

Code:
>>>0xCD

205

Hex form is 0xXX

>>>010

8

This is ocatal, but in version 3 it changed to following

Code:
>>>0o10

8

Now, we've reached the end of Chapter 2 Smile

Thanks for reading.
Ref : Multiple Sources
MrGeek @ HC :-> logout

Quote:int x;

Another example

Quote:>>>x = 3
>>>y = 3
>>>print(x*y)
9

First variable x is assgined integer 3
Then variable y is assgined integer 3
After that, print function is used to output the results.
Now you should have grub the basics of variable Biggrin

)

Quote:1. Definition must be first declared
2. Write the definition
3. Call the Defininition
are bound to be followed.

Code:
#!usr/bin/env python

#This is a comment

Print('hello')

#This is a comment again

Open up Python shell. Let's get started.

Code:
>>> 1+1

2

>>>1/2

0

Now why 1 divided by 2 didn't result in 0.5?
Because Python took it as integer. But it's not the problem anymore in python version 3.

Code:
>>>1.0/2.0

0.5

In this way, we can calcualte basic Arithmetic Operations, such as addition, subtruction, multiplication, and division.
“+ - / *”
Another one

Code:
>>>1%2

"%" operator is used to calculate remainder of a division.

Code:
>>>3**2

9

"**" means power

Code:
>>>-3**2

-9

>>>(-3)**2

9

Latest version didn't have the buffer overflow anymore!
Hexadecimal and Octal are also supported

Code:
>>>0xCD

205

Hex form is 0xXX

>>>010

8

This is ocatal, but in version 3 it changed to following

Code:
>>>0o10

8

Now, we've reached the end of Chapter 2 Smile

Thanks for reading.
Ref : Multiple Sources
MrGeek @ HC :-> logout

RE: Python Tutorial Chapter 2 - More Python - Deque - 05-17-2013

Hi MrGeek. Again some comments from my side.

Quote:Python is just like powerful language such as C and java, supports 3 data types for scientific calculations. The three DATA TYPES are :

That sounds like there are only these three data types. There are more and you mentioned some of them later. I would be more precise here.

Quote:Functions are vital in every programming lanugages.

No. In most programming languages, not in every programming language.

Quote:1. Definiation must be first declared
2. Write the defination
3. Call the Definination
are bound to be followed.

That doesn't make sense for a beginner, nor is it correct.
There is nothing like definination or defination or definiation.
If you are talking about definition and declaration you must explain the terms before you use them. No programming beginner will know what you are talking about.

If you are unsure about something, you should leave it away. It is no good making tutorials if you write wrong stuff in them.

Quote:Commenting makes the program more readable and easier to debug.

Comments are a perfume for bad smelling code. Wink

Quote:Python do not have long integer type as C language. It's included in integer type.
This might be a weakness.

Why a weakness?

Also: This is confusing. Python has plain integer and long integer type, see: http://docs.python.org/2/library/stdtypes.html
But the plain integer in python is the same as the data type long in C.
So saying it has no long integer is wrong. It actually has no equivalent to the int in C.

Quote:Ref : Multiple Sources

That's not really a valid way to state sources.

Last but not least: What Python version is this about? 2.x is not compatible to 3.x, but it is still used more than 3.x

Regards
Deque

RE: Python Tutorial Chapter 2 - More Python - Deque - 05-17-2013

Hi MrGeek. Again some comments from my side.

Quote:Python is just like powerful language such as C and java, supports 3 data types for scientific calculations. The three DATA TYPES are :

That sounds like there are only these three data types. There are more and you mentioned some of them later. I would be more precise here.

Quote:Functions are vital in every programming lanugages.

No. In most programming languages, not in every programming language.

Quote:1. Definiation must be first declared
2. Write the defination
3. Call the Definination
are bound to be followed.

Quote:Commenting makes the program more readable and easier to debug.

Comments are a perfume for bad smelling code. Wink

Quote:Python do not have long integer type as C language. It's included in integer type.
This might be a weakness.

Quote:Ref : Multiple Sources

That's not really a valid way to state sources.

Last but not least: What Python version is this about? 2.x is not compatible to 3.x, but it is still used more than 3.x

Regards
Deque

RE: Python Tutorial Chapter 2 - More Python - Ex094 - 05-17-2013

NIce work but I have some suggestions about your tutorial,

1) Your explanation about Functions in Python is not clear and lacks proper examples

2) You've mention under the Commonly used functions as

Code:
Commonly used Functions

1.print()

2.input() / raw_input()

2.float

3.complex

This might confuse beginners as they will think all of them are separate functions like input() and raw_input(). You should have mentioned the Input() is used in Python3.3 and raw_input() in previous version that's 2.7. I recommend you write functions about single python versions that you are using otherwise beginners are going to get confused.

3) This is just a suggestion, For me whitespaces in code makes it more readable. Your example like:

Code:
>>2+3

If you read other tutorials like Learn Python the Hard Way, they have too stated it's better to leave spaces so that it's more readible like:

Code:
>>> 2 + 3

For better example here's a simple add function:

No whitespaces

Code:
def addition(x,y):

    return x+y

With spacing

Code:
def addition(x, y):

    return x + y

You can see the difference yourself.

4) You didn't mention anything about indentation as it's important for a language like Python, one wrong indent in a long code and a beginner is gonna have a heck of a time finding it.

Code:
Commonly used Functions

1.print()

2.input() / raw_input()

2.float

3.complex

Code:
>>2+3

If you read other tutorials like Learn Python the Hard Way, they have too stated it's better to leave spaces so that it's more readible like:

Code:
>>> 2 + 3

For better example here's a simple add function:

No whitespaces

Code:
def addition(x,y):

    return x+y

With spacing

Code:
def addition(x, y):

    return x + y

RE: Python Tutorial Chapter 2 - More Python - MrGeek - 05-17-2013

@Deque
Firstly, I would like to thank sis Smile

I'm afraid of my thread being with no reply .
Now here replies and I can empower my knowledge.

Quote:That sounds like there are only these three data types. There are more and you mentioned some of them later. I would be more precise here.

Yep, there are more than 3 data types , I missed the word ' in genera '.

Quote:That doesn't make sense for a beginner, nor is it correct.
There is nothing like definination or defination or definiation.
If you are talking about definition and declaration you must explain the terms before you use them. No programming beginner will know what you are talking about.

If you are unsure about something, you should leave it away. It is no good making tutorials if you write wrong stuff in them.

I miss spelled. My grammar sucks. Sorry about that. Fixing it now.

Quote:Also: This is confusing. Python has plain integer and long integer type, see: http://docs.python.org/2/library/stdtypes.html
But the plain integer in python is the same as the data type long in C.
So saying it has no long integer is wrong. It actually has no equivalent to the int in C.

Well, you point me to the python2 documentation. But I see no long in python3 Documentation. I am making this to sure.

Quote:What Python version is this about? 2.x is not compatible to 3.x, but it is still used more than 3.x

I am comparing python3 with python2 Smile

And Thanks again for reading.

@Ex094
Thanks bro , you guys are always read my threads carefully Biggrin

I am glad to see that.

Quote:1) Your explanation about Functions in Python is not clear and lacks proper examples

I already said I will explain more about them in later chaps.

Quote:This might confuse beginners as they will think all of them are separate functions like input() and raw_input(). You should have mentioned the Input() is used in Python3.3 and raw_input() in previous version that's 2.7. I recommend you write functions about single python versions that you are using otherwise beginners are going to get confused.

You are right! I have responsibility for not explaining input vs raw_input & there is no raw_input in python3

Quote:4) You didn't mention anything about indentation as it's important for a language like Python, one wrong indent in a long code and a beginner is gonna have a heck of a time finding it.

You are right again! I missed that part.
"Single-Quoted Strings and Escaping Quotes"

Also , writing a programming post is more difficult than a hacking post.
Regards
Mr.Geek