# 1.5 Itse1359-1030-variables and identifiers  (Page 3/7)

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## Numbers

Numbers can be any of the digit characters between and including 0 and 9.

## Style

Click PEP 8 -- Style Guide for Python Code to learn more about how to create identifiers for variables and other programming elements as well.

## Start the interactive Python environment

The first thing that you need to do is to start the interactive programming environment. If you have forgotten how to do that, see the module titled Itse1359-1010-Getting Started .

## Create and use some variables

The interactive fragment shown in Figure 1 :

• Creates two variables named x and y,
• Populates them by assigning values of 6 and 5 to them respectively
• Adds their values together to produce the sum value of 11.
Figure 1 . Create and use some variables.
```>>>x=6 # create and populate x>>>y=5 # create and populate y>>>x+y # add x to y and display the sum 11>>>```

## Back to the pigeonholes

Using the informal jargon from an earlier paragraph, two pigeonholes are established in memory and are given nicknames of x and y.

## The assignment operator

Integer values of 6 and 5 are stored in the two pigeonholes using the assignment operator (=).

The use of the assignment operator in this fashion causes the value of its right operand to be stored in the pigeonhole identified by its left operand .

## What is an operand ?

If you don't recognize the use of the term operand, see the earlier module titled Itse1359-1020-Numbers for an explanation.

In this case, the right operands of the assignment operators are literal numeric values .

The left operands of the assignment operators are the nicknames identifying the two memory locations that constitute the variables named x and y.

The values are retrieved from eachpigeonhole and added together in the third line of code. The result of the addition (11) is displayed as output from the expression x+y .

## Assigning the same value to several variables

Python allows you to assign the same value to several variables, causing them to come into existence (begin to occupy memory) at the same time if necessary

Consider the interactive fragment shown in Figure 2 .

Figure 2 . Assigning the same value to several variables.
```>>>a=b=c=10 # assign 10 to several variables>>>a+b+c # add them together 30>>>a=b=c=20 # assign 20 to same variables>>>a+b+c # add them together 60>>>```

## Create three variables

The first line of code in Figure 2 creates three variables named a , b , and c , and assigns a value of 10 to each of them.

They are then added together, in the second line of code, to produce an output value of 30.

## Assign different values

The fourth line of code assigns the value of 20 to the same three variables, replacing what was previously there with the new value. Againthey are added together, this time producing an output value of 60.

## A more comprehensive explanation

Pigeonhole explanations are good for starters, but let's move on to a more comprehensive and technically correct explanation.

According to the Python gurus, everything (or at least almost everything) in Python is an object. I indicated earlier that data values are stored in variables.In reality, that is not the case. Figure 3 shows the truth about pigeonholes, variables, and objects.

anyone know any internet site where one can find nanotechnology papers?
research.net
kanaga
Introduction about quantum dots in nanotechnology
what does nano mean?
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
it is a goid question and i want to know the answer as well
Maciej
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
What is lattice structure?
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
what's the easiest and fastest way to the synthesize AgNP?
China
Cied
types of nano material
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
how did you get the value of 2000N.What calculations are needed to arrive at it
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