Python Programs on Lists

Python Programs on Lists:

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

Ans.

a = [10,20,30,20,10,50,60,40,80,50,40]
 
dup_items = set()
uniq_items = []
for x in a:
    if x not in dup_items:
        uniq_items.append(x)
        dup_items.add(x)
 
print(dup_items)

2.Write a Python program which accepts a sequence of comma-separated numbers from user and generate a list and a tuple with those numbers.

Ans.

values = input("Input some comma seprated numbers : ")
list = values.split(",")
tuple = tuple(list)
print('List : ',list)
print('Tuple : ',tuple)

3.Write a Python program to create a histogram from a given list of integers.

Ans.

def histogram( items ):
    for n in items:
        output = ''
        times = n
        while( times > 0 ):
          output += '*'
          times = times - 1
        print(output)
 
histogram([2, 3, 6, 5])

4.Write a Python program to concatenate all elements in a list into a string and return it.

Ans.

def concatenate_list_data(list):
    result= ''
    for element in list:
        result += str(element)
    return result
 
print(concatenate_list_data([2, 50, 12, 9]))

5.Write a Python program to filter the positive numbers from a list.

Ans.

nums = [34, 1, 0, -23]
print("Original numbers in the list: ",nums)
new_nums = list(filter(lambda x: x >0, nums))
print("Positive numbers in the list: ",new_nums)

6.Write a Python program to remove and print every third number from a list of numbers until the list becomes empty.

Ans.

def remove_nums(int_list):
  #list starts with 0 index
  position = 3 - 1
  idx = 0
  len_list = (len(int_list))
  while len_list>0:
    idx = (position+idx)%len_list
    print(int_list.pop(idx))
    len_list -= 1
nums = [10,20,30,40,50,60,70,80,90]
remove_nums(nums)

7.Write a Python function that takes a list of words and returns the longest one.

Ans.

def find_longest_word(words_list):
    word_len = []
    for n in words_list:
        word_len.append((len(n), n))
    word_len.sort()
    return word_len[-1][1]
 
print(find_longest_word(["PHP", "Java", "Python"]))

8.Write a Python program to accept a filename from the user and print the extension of that.

Ans.

filename = input("Input the Filename: ")
f = filename.split(".")
print ("The extension of the file is : " + f[-1])