TYL - P3 Lists and Files Discussion (largest, remove duplicates, at least 1 common element)

TYL - P3 Lists and Files Discussion

 (Largest Number, Remove Duplicates, common element)


1. Write a Python program to get the largest number from a list.

use max() on a list to find the largest number or use a variable.

Program:

def largestNumber(t):
    return max(t)

 elements=[48,57,69,58,23,3]
largest = largestNumber(elements)

 print("Largest Number:", largest)

When you use a variable, you can initially set it to None.

Program:

def largestNumber(t):
    largest = None
    for e in t:
        if largest == None or largest<e:
            largest=e

     return largest

 elements=[48,57,69,58,23,3]
largest = largestNumber(elements)

 print("Largest Number:", largest)

Output:

python tyl_lists.py
Largest Number: 69


2. Write a Python program to remove duplicates from a list.


If you use the function set() it will automatically remove duplicates as it is it's implied functionality.  However, it returns an object of type "set".
So, we convert it back to list using list()
Eg.
>>> s=set([1,1,2])
>>> s
{1, 2}
>>> type(s)
<class 'set'>
>>> t=list(s)
>>> t
[1, 2]
>>> type(t)
<class 'list'>


Program:

def removeDuplicates(t):
    return list(set(t))

 elements=[48,57,69,58,23,58,69,3]
wodup=removeDuplicates(elements)
print("Without Duplicates:", wodup)

Solution without using sets

Create an empty list.
Use an appropriate loop to remove items from the existing list.
only add to new list if the element is not already present.
you can do it this way to practice some functions learnt in class such as pop() append().

Program

def removeDuplicates(t):
    #return list(set(t))
    wodup=[]
    while t:
        e=t.pop()
        if e not in wodup:
            wodup.append(e)
           
    return wodup

 elements=[48,57,69,58,23,58,69,3]
wodup=removeDuplicates(elements)
print("Without Duplicates:", wodup)


Output:

Without Duplicates: [3, 69, 58, 23, 57, 48]

3. Write a Python function that takes two lists and returns True if they have at least one common member.

loop through each element in either of the two lists
use the "in" operator to check if that element is in the other list.
If in a function, return True.  It would stop the loop there
Or set up a boolean variable, set it initially to False.  Once a common element is found, set it to True, break out of the loop, return the variable.

Program:

def checkCommon(t1, t2):

     for e in t1:
        if e in t2:
            return True

     return False

 listOne=[1,3,5,6,4]
listTwo=[3,4,5,8]
listThree=[56,78,45]
print("List One and List Two have a common element:",checkCommon(listOne, listTwo) )
print("List One and List Three have a common element:",checkCommon(listOne, listThree) )


With a variable

def checkCommon(t1, t2):

     common=False
    for e in t1:
        if e in t2:
            common=True
            break

     return common


Output:

List One and List Two have a common element: True
List One and List Three have a common element: False

Comments

Post a Comment

Popular posts from this blog

TYL - Food Corner Program

Food Corner Program. We will make this program more robust after you learn try-catch.  For now, we will calculate for only 1 order.  Again, later you can use loops to calculate for many orders.  As we have not learnt any data structures as lists, dictionaries etc, we will not use them now. FoodCorner home delivers vegetarian and non-vegetarian combos to its customer based on order. A vegetarian combo costs Rs.120 per plate and a non-vegetarian combo costs Rs.150 per plate. Their non-veg combo is really famous that they get more orders for their non-vegetarian combo than the vegetarian combo. Apart from the cost per plate of food, customers are also charged for home delivery based on the distance in kms from the restaurant to the delivery point. The delivery charges are as mentioned below: Distance in kms          Delivery charge in Rs. Per kms For first 3 kms                       ...
Read more

Classes and objects solution

Image
Question 1 Write a definition for Student class Define __init__(self, marks=[]) for the Student class Define add_marks(self,lst) that appends mark to the marks list Create two students, s1 and s2. Add [25,45,65] to s1 Print marks of s1 and s2 Observe what happens? Fix the code. Initial Implementation class Student:     def __init__(self, marks=[]):         self.marks = marks     def add_marks(self,lst):         self.marks.extend(lst) s1= Student() s2=Student() s1.add_marks([25,45,65]) print('Contents of s1',s1.marks) print('Contents of s2',s2.marks) Output: Contents of s1 [25, 45, 65] Contents of s2 [25, 45, 65] Observation: list is getting added to s1, but s2 also shows the same contents.  What is expected is an empty list for s2 but s1 consisting of [25,45,65] Why this happens? https://stackoverflow.com/questions/4841782/python-constructor-and-default-value Solution: def __ini...
Read more

TYL - Salary Hike - Python Problem

Salary Hike Problem using Python We are not going to use any complex data structures in Python here. You will need to know the if else construct.  After we learn try... catch we will make this program more robust. if  condition:      statements      .... elif condition:      statements     ... ... else:     statement An organization has decided to provide salary hike to its employees based on their job level. Employees can be in job levels 3, 4 or 5. Hike percentage based on job levels are given below: Job level         Hike Percentage (applicable on current salary) 3                        15 4                         7 5                         5 In case of invalid job level, consider hike percentage to be ...
Read more