Chapter 1 Numbers & Expressions, 'Beginning Python From Novice to Professional' / Цифры и выражения

Addition, subtraction, сложение, вычитание
>>> 2+2
4

>>>3-2
1

(!) Division, деление

>>>1/2
0

>>>1.0/2.0
0,5

>>>1/2.
0.5
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From _future_import division

>>>1/2
0.5

>>>1//2
0
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Reminder operator / оператор остатка

>>>1%2
1
>>> 10%3
1
>>> 10%4
2
>>> 10%5
0
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Multiplication / умножение

>>> 3*333
999
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Exponentiation / Возведение в степень

>>> 2**3
8
>>> -3**2
-9
>>> (-3)**2
9
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Variables

Assignment

x = 3

Expression

x*2
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Statements—the instructions

>>>print 2*2
4
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Getting input from user ( привет, "По галактике автостопом")

>>> input ('The meaning of life: ')
The meaning of life: 42
42

>>> x = input ('x: ')
x: 30
>>> y = input ('y: ')
y: 40
>>> x*y
1200

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Functions

>>> 2**3
8
>>> x=pow(2,3)
>>> x
8

>>> 10+pow(2,3*5)/3
10932

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Absolute number

>>> abs(-10)
10

Rounding
>>> 1/2
0

>>> round (1.0/2.0)
1.0

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Modules

>>> import math
>>> math.floor (32.9)
32.0
>>> int(math.floor(32.9))
32

Import only one function

>>> from math import sqrt
>>> sqrt(49)
7.0

SQRT from negative number - imaginary number
>>> import cmath
>>>cmath.sqrt(-49)
7j


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Input vs raw_input

>>> name = input ('What is your name?')
What is your name?"Dron"
>>> print "Hello, "+name+"!"
Hello, Dron!
>>> name = raw_input("What isyour name?")
What isyour name?Dron
>>> print "Hello, "+name+"!"

Hello, Dron!
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>>> path = 'C:\nowhere'
>>> path
'C:\nowhere'
>>> print path
C:
owhere
>>> path = 'C:\\nowhere'
>>> print path
C:\nowhere
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>>> print r'C:\nowhere'
C:\nowhere