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Tuples can be concatenated

As shown in Listing 1 , tuples support the concatenation (+) operator. You can concatenate two or more tuples to produce a new tuple. This program creates twosimple tuples, and then concatenates them to create a third tuple.

Figure 1 shows the output produced by the code in Listing 1 . By now, the creation and display of simple tuples should be very familiar to you based onearlier modules. Therefore, I won't discuss this part of the program further.

Figure 1 . Output from the code in Listing 1.
(1, 2, 'A', 'B')

Unusual syntax

The code in Listing 2 is not quite so straightforward. In fact, it looks rather strange if you come from a conventional C, C++, or Java programming background.

Listing 2 . Unpack the tuple and print individual elements.
# Unpack the tuple and print individual elements w,x,y,z = t3print(w) print(x)print(y) print(z)

Figure 2 shows the output produced by the code in Listing 2 .

Figure 2 . Output from the code in Listing 2.
1 2A B

If you compare this output with the original tuple in Listing 1 , or with the previous output in Figure 1 , you will see that each of the individual items in the tuple (in left-to-right order) were assigned respectively to the variables named w , x , y , and z .

Thus, the lines of output produced by printing these four variables in Figure 2 match the items in the original tuple that was created in Listing 1 and displayed in Figure 1 .

Packing and unpacking a tuple

Version 3 of The Python Tutorial -- 5.3. Tuples and Sequences refers to the first, second, and third statements in Listing 1 as tuple packing using the following example:

The statement t = 12345, 54321, 'hello!' is an example of tuple packing: the values 12345, 54321 and 'hello!' are packed together in a tuple. The reverse operation is also possible

An early version of The Python Tutorial -- 5.3 Tuples and Sequences refers to the first statement in Listing 2 as tuple unpacking .

The current version of The Python Tutorial -- 5.3. Tuples and Sequences (September 2014) refers to that operation more generally as sequence unpacking .

That tutorial continues by telling us

"... sequence unpacking requires that there are as many variables on the left side of the equals sign as there are elements in the sequence."

If you try to run a program that doesn't meet these criteria, you will get an error similar to the following:

ValueError: too many values to unpack (expected 3)

Unpack the tuple into the mutable list

Just to make things a little more interesting, I decided to combine the use of a tuple (an immutable list) and a regular mutable list in this program.

Listing 3 contains the code to create a mutable list populated with five string characters.

Listing 3 . Unpack the tuple into the mutable list.
# Create and print a list L1 = ["a","b","c","d","e"]# Unpack tuple into the list and print it print(L1)L1[0],L1[1],L1[2],L1[3]= t3 print(L1)

Then the list is displayed, as shown by the first line of text in Figure 3 . The first line of output in Figure 3 shows the contents of the list just after it is created and populated.

Questions & Answers

anyone know any internet site where one can find nanotechnology papers?
Damian Reply
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
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.
what is the actual application of fullerenes nowadays?
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.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
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.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
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