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Figure 3 . Output from the code in Listing 3.
['a', 'b', 'c', 'd', 'e'] [1, 2, 'A', 'B', 'e']

Then the code in Listing 3 unpacks the four-element tuple referred to by t3 into the first four elements in the list. (Remember, a list is mutable, so the values of its items can be changed.)

Then the contents of the list are displayed again producing the second line of text in Figure 3 . As you can see from Figure 3 , the first four items in the list were replaced by the four items from the tuple. The fifth item in the list was not modified.

Complete program listing

A complete listing of the program discussed above is provided in Listing 4 .

Listing 4 . Complete program listing.
# Illustrates unpacking a tuple #------------------------------# Create a pair of tuples t1 = 1,2t2 = "A","B" # Concatenate and print themt3 = t1 + t2 print(t3)# Unpack the tuple and print individual elements w,x,y,z = t3print(w) print(x)print(y) print(z)# 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)

Figure 4 shows the output from the code in Listing 4 .

Figure 4 . Output from the code in Listing 4.
(1, 2, 'A', 'B') 12 AB ['a', 'b', 'c', 'd', 'e'][1, 2, 'A', 'B', 'e']

Visualization of the tuples in the program

Figure 5 shows a visualization of the tuples in the program after the first five statements in the code block have been executed.This is a case where you need to step through the program and observe changes in the diagram on the right to appreciate the behavior of the program.

Figure 5. Visualization of the tuples in the program.

Visualization of the tuples in the program.

Run the program

I encourage you to copy the code from Listing 4 . Execute the code and confirm that you get the same results as those shown in Figure 4 . Experiment with the code, making changes, and observing the results of your changes. Make certain that youcan explain why your changes behave as they do.

For example, you might want to try the following experiment. There is a line in the program shown in Listing 4 that reads as follows:

L1 = ["a","b","c","d","e"]

Modify the program, changing this line so that it reads as follows:

L1 = ("a","b","c","d","e")


L1 = "a","b","c","d","e"

By now you should recognize that either of these modifications will change L1 from an ordinary mutable list to a tuple (an immutable list) .

Now execute the modified program. Your output should look something like that shown in Figure 6 .

Figure 6 . Output from the modified program.
(1, 2, 'A', 'B') 12 AB ('a', 'b', 'c', 'd', 'e')Traceback (most recent call last): File "1359-1130-07.py", line 24, in<module>L1[0],L1[1],L1[2],L1[3]= t3 TypeError: 'tuple' object does not support item assignment

Everything should work well until the attempt is made to unpack the tuple named t3 and to assign the items from that tuple into the individual items of the new tuple named L1 .

The items in a tuple are immutable, meaning that they cannot be changed. Therefore, the program crashes at this point with the error shown in Figure 6 .


This section contains a variety of miscellaneous information.

Housekeeping material
  • Module name: Itse1359-1130-Unpacking Tuples
  • File: Itse1359-1130.htm
  • Published: 10/19/14
  • Revised: 01/31/16

Financial : Although the Connexions site makes it possible for you to download a PDF file for thismodule at no charge, and also makes it possible for you to purchase a pre-printed version of the PDF file, you should beaware that some of the HTML elements in this module may not translate well into PDF.

I also want you to know that, I receive no financial compensation from the Connexions website even if you purchase the PDF version of the module.

In the past, unknown individuals have copied my modules from cnx.org, converted them to Kindle books, and placed them for sale on Amazon.com showing me as the author. Ineither receive compensation for those sales nor do I know who does receive compensation. If you purchase such a book, please beaware that it is a copy of a module that is freely available on cnx.org and that it was made and published withoutmy prior knowledge.

Affiliation : I am a professor of Computer Information Technology at Austin Community College in Austin, TX.


Questions & Answers

what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
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.
yes that's correct
I think
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
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
analytical skills graphene is prepared to kill any type viruses .
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
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
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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