<< Chapter < Page Chapter >> Page >

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

what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
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.
Bharti
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
Daniel
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Good
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!





Source:  OpenStax, Itse 1359 introduction to scripting languages: python. OpenStax CNX. Jan 22, 2016 Download for free at https://legacy.cnx.org/content/col11713/1.32
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Itse 1359 introduction to scripting languages: python' conversation and receive update notifications?

Ask