Python Puzzle Remove even numbers

Python Puzzle Remove even numbers

# Wrong approach (incorrect - using For loop)

def removeEven(List):

    print(id(List)) # 139909029905664

    for each in List:

       i f each % 2 == 0:

          List.remove(each)

myList = [152, 168, 154, 32, -55, 81, 146, -34, -124, -9, 4, -31, -131, -86, -190, -38]

print(id(myList)) # 139909029905664

print(myList) # [1, 2, 4, 5, 10, 6, 3]

removeEven(myList)

print(myList) # [168, 32, -55, 81, -34, -9, -31, -131, -190]

# Wrong as when element gets deleted, index goes down

print('-' * 60)

# Correct approach (using While loop)

def removeEvenNew(List):

    print(id(List))

    i = 0

    while i < len(List):

      if List[i] % 2 == 0:

          List.remove(List[i])

      else:

          i += 1 

myList = [152, 168, 154, 32, -55, 81, 146, -34, -124, -9, 4, -31, -131, -86, -190, -38]

print(id(myList))

print(myList) # 

removeEvenNew(myList)

print(myList) # [-55, 81, -9, -31, -131]

Output:

140407115793920

[152, 168, 154, 32, -55, 81, 146, -34, -124, -9, 4, -31, -131, -86, -190, -38]

140407115793920

[168, 32, -55, 81, -34, -9, -31, -131, -190]

------------------------------------------------------------

140407114861888

[152, 168, 154, 32, -55, 81, 146, -34, -124, -9, 4, -31, -131, -86, -190, -38]

140407114861888

[-55, 81, -9, -31, -131]

Learning For While loops in Python

#!/usr/local/bin/python2.7

'''
    Learning For/While loops in Python
    File name: for_while_loop_python.py
    Author: Prabhath Kota
    Date: June 22, 2018
    Python Version: 2.7
'''

'''
Topics:
For loop
While loop
range
break
continue
enumerate
'''

print '----------------For loop---------------------'
freedom_fighters = ["Lala Lajipati Rai", "Dadabhai Naoroji", "Rajendra Prasad", "Sarojini Naidu", "Dadabhai Naoroji", "Lal Bahadur Shastri"]
print freedom_fighters
for each in freedom_fighters:
print each

print '----------------For loop Break---------------------'
print freedom_fighters
#Print only first 4 elements using Break statement
#Enumerate will get you index of the element as well - starting from 0
#enumerate(freedom_fighters) will start the index from 0
#enumerate(freedom_fighters, 1) will start the index from 1
for index,each in enumerate(freedom_fighters, 1):
print index, each
if index == 4:
break
print '----------------For loop Continue---------------------'
print freedom_fighters
#Print only even elements from the list
for index,each in enumerate(freedom_fighters, 1):
if index % 2 == 1: #Odd elements
continue
else: #Even Elements
print index, each

print '----------------For loop Range---------------' 
squares = []
print range(1,10)
for x in range(0,10):
squares.append(x**2)
print (squares)

print '----------------While loop---------------'
#Try to avoild While loops, use only unless otherwise reequired
#If you sometimes don't handle it, it may end up in infinite loop
i = 0
squares = []
while(i < 10):
squares.append(i**2)
i += 1
print squares

Output:

----------------For loop---------------------

['Lala Lajipati Rai', 'Dadabhai Naoroji', 'Rajendra Prasad', 'Sarojini Naidu', 'Dadabhai Naoroji', 'Lal Bahadur Shastri']

Lala Lajipati Rai

Dadabhai Naoroji

Rajendra Prasad

Sarojini Naidu

Dadabhai Naoroji

Lal Bahadur Shastri

----------------For loop Break---------------------

['Lala Lajipati Rai', 'Dadabhai Naoroji', 'Rajendra Prasad', 'Sarojini Naidu', 'Dadabhai Naoroji', 'Lal Bahadur Shastri']

1 Lala Lajipati Rai

2 Dadabhai Naoroji

3 Rajendra Prasad

4 Sarojini Naidu

----------------For loop Continue---------------------

['Lala Lajipati Rai', 'Dadabhai Naoroji', 'Rajendra Prasad', 'Sarojini Naidu', 'Dadabhai Naoroji', 'Lal Bahadur Shastri']

2 Dadabhai Naoroji

4 Sarojini Naidu

6 Lal Bahadur Shastri

----------------For loop Range---------------

[1, 2, 3, 4, 5, 6, 7, 8, 9]

[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]

----------------While loop---------------

[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]

[Finished in 0.2s]

For Loop in Python

inspiring_ppl = ["Mahatma Gandhi", "Mother Teresa", "Paul Coelho", "Bill Gates", "Steve Jobs"]

for person in inspiring_ppl:
    print "Hello", person + ", how are you?"  #3.X Version
     #print("Hello", person + ", how are you?")  #2.X Version