May 19, 2020

Python 2 Vs 3


Python 2Python 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 int3/2 ==> 1.5
Strings default stores as AsciiStrings 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 evaluationrange() - 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

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