Structured data, Python Programming

Structured data

We will often  want  to work  with  large  groups of data.   Rather  than  providing  each  number its own  value,  we need  to manage the data  into natural structures: grocery  lists, matrices, groups of employee medical records. We will explain  a simple  but  enormously useful  and ?exible list, which is conveniently create into Python: the list. The precise information  of how lists are shown inside a computer vary from language to language. We will take an abstract model  in which we think of a list as an ordered sequence of memory locations that numbers. So, for example, in Python, we may show a list of three integers as:

 

644_structured data.png

 

 

Now that we have lists, we have some new kinds  of statements, which let us extract elements of a list by specifying their indices.   An index  of 0 related to the ?rst  element of a list.  An index  of -1 related to the last element So, if a is bound as above, then we would have:

 

>>> a[0]

>>> a[2] 

>>> a[-1] 

>>> a[3] 

 

Traceback (most recent call last): File "", line 1, in IndexError: list index out of range.Note that if we attempt to access an element of the list that is not present, then a exception is generated.

 

 

847_structured data  2.png

 

 

It is also possible  to have  an empty list, which  is given in Python as []. We will show it in our memory diagrams as a short box. So example, this list  looks like this in memory:

>>> z = [3, [], [[]]]

 

 

 

515_structured data  3.png

 

Python has a useful method, len, which takes a list as an argument and gives its size. It does not look inside  the elements of the list-it just returns the number of elements at the top level of list. So, we take

 

>>> len([1, 2, 3])

3

>>> len([[1, 2, 3]])

1

 

Posted Date: 8/11/2012 1:38:38 AM | Location : United States







Related Discussions:- Structured data, Assignment Help, Ask Question on Structured data, Get Answer, Expert's Help, Structured data Discussions

Write discussion on Structured data
Your posts are moderated
Related Questions
I have a C++ code (10-15 line) which i need to re-write in python with the help of ctypes library. Is it possible i can get some help with it? Thanks & regards Tanmoy

#ques Write the pseudocode (use a word processor please) and the Python 3.0 program for the following problem. A monkey is being fed some food. Read in the starting weight in lbs:o

1 Low Level Exploits 1.1 Savegames Jimmy is becoming increasingly frustrated at the computer game hes playing. He has a save right before the levels boss but he needs either more

1)    Write a python programmecomparing for and while loops like the following. Math Times table For Loop: 2x1=2 2x2=4 ..... 2x12=24 While Loop: 3x1=3 3x

Python  Style Software  engineering courses  often  provide very  rigid  guidelines on the style of programming, generally the appropriate value of indentation, or what  to us

Structured assignment Once  we have  tuples and lists, we may use  a nice trick  in assignment expression, based  on the packing and unpacking of tuples. >>> a, b, c = 1, 2

Data array A has data series from 1,000,000 to 1 with step size 1, which is in perfect decreasing order. Data array B has data series from 1 to 1,000,000, which is in random order.

The goal of this exercise is to write a \business phrase" generator, which each time it is called produces lines of business speak, such as: It's time that we became uber-effici

Python Programs You must submit the source code and samples of output for each program.Please do not provide python file (eg. Filename.py). Copy all source code to one word fi

Write an algorithm for a program that shows the use of all 6 math functions. Write, test, and debug the program using Python. SAMPLE OUTPUT (not including author/program infor