Python 2 Vs 3

Python 2	Python 3
input() may store as int, string raw_input() stores str always	input() function was fixed in Python 3 so that it always stores the user inputs as str
print "Hi" print("Hi")	print("Hi")
3/2 ==> floor(1.5) => 1 (defaults to floor), return int	3/2 ==> 1.5
Strings default stores as Ascii	Strings default stores as unicode Unicode is a superset of ASCII and hence, can encode more characters including foreign ones.
sorted(employees.items(), key=lambda(x,y): y['age'])	sorted(employees.items(), key=lambda x: x[1]['age'])
	AsyncIO
	Fstrings
	It is recommended to use __future__ imports it if you are planning Python 3.x support for your code
xrange() - Lazy evaluation	range() - Lazy evaluation
except NameError, err:	except NameError as err:
my_generator = (letter for letter in 'abcdefg') next(my_generator) my_generator.next()	my_generator = (letter for letter in 'abcdefg') next(my_generator)
print 'Python', python_version() i = 1 print 'before: i =', i print 'comprehension: ', [i for i in range(5)] print 'after: i =', i Python 2.7.6 before: i = 1 comprehension: [0, 1, 2, 3, 4] after: i = 4	Python 3.x for-loop variables don’t leak into the global namespace anymore! print ('Python', python_version()) i = 1 print 'before: i =', i print 'comprehension: ', [i for i in range(5)] print 'after: i =', i Python 3.4.1 before: i = 1 comprehension: [0, 1, 2, 3, 4] after: i = 1
print range(3) print type(range(3)) [0, 1, 2] <type 'list'>	print range(3) print type(range(3)) print(list(range(3))) range(0, 3) <class 'range'> [0, 1, 2]
round(15.5) # 16.0 round(16.5) # 17.0	Bankers rounding round(15.5) # 16 round(16.5) # 16

Python Sorted 2 Vs 3 versions

employees = {1000: {'name': 'Sahasra','country': 'India', 'age': 25}, \
   1001: {'name': 'Peter','country': 'US', 'age': 21}, \
   1002: {'name': 'John','country': 'US', 'age': 36}, \
   1003: {'name': 'Sarayu','country': 'India', 'age': 30},\
   1004: {'name': 'Akio','country': 'Japan', 'age': 60}, \
   1005: {'name': 'Anand','country': 'India', 'age': 50}, \
   1006: {'name': 'Vidya','country': 'India', 'age': 32}, \
   1007: {'name': 'Salma','country': 'Bangladesh', 'age': 23},}

# Works in Python 2.7 only
ss = sorted(employees.items(), key=lambda(x, y): y['age'])
print(ss)

# Works in Python 2.7 and 3.7
# Using parentheses to unpack the arguments in a lambda is not allowed in ss ss = sorted(employees.items(), key=lambda x: x[1]['age'])
print(ss)


Output:

[(1001, {'country': 'US', 'age': 21, 'name': 'Peter'}), (1007, {'country': 'Bangladesh', 'age': 23, 'name': 'Salma'}), (1000, {'country': 'India', 'age': 25, 'name': 'Sahasra'}), (1003, {'country': 'India', 'age': 30, 'name': 'Sarayu'}), (1006, {'country': 'India', 'age': 32, 'name': 'Vidya'}), (1002, {'country': 'US', 'age': 36, 'name': 'John'}), (1005, {'country': 'India', 'age': 50, 'name': 'Anand'}), (1004, {'country': 'Japan', 'age': 60, 'name': 'Akio'})]

[(1001, {'country': 'US', 'age': 21, 'name': 'Peter'}), (1007, {'country': 'Bangladesh', 'age': 23, 'name': 'Salma'}), (1000, {'country': 'India', 'age': 25, 'name': 'Sahasra'}), (1003, {'country': 'India', 'age': 30, 'name': 'Sarayu'}), (1006, {'country': 'India', 'age': 32, 'name': 'Vidya'}), (1002, {'country': 'US', 'age': 36, 'name': 'John'}), (1005, {'country': 'India', 'age': 50, 'name': 'Anand'}), (1004, {'country': 'Japan', 'age': 60, 'name': 'Akio'})]