Output:


 print(3)
 print("Hello World")
 

 A = 123
 B = 'ABC'
 C = 456
 D = 'DEF'
 print(A, B, C, D)

Calculation:

Variable:

cash =100 
apple =10
remain = cash – apple
print(remain)

x = 1;
x = x + 1
print(x)

Type:


 1---Integer
 "1"--- String
 True---Boolean
 [1, 2, 3]---List
 (1, 2, 3)--- Tuple
 ["name": "Linda"]---Dictionary
 two different type cannot operate together

String:


 print("Hello World")
 print("This is "+"BCIS") #concatenate
 print("Over hill, over dale,\n"+"Thorough bush,thoroughbrier")
 print(1 + 2)
 print(1 + "ss") #wrong
 print("1" + "ss")
 print(str(1) + "ss")
 print("This year is %d"%2016)
 print("I am %d years old I have %d brothers"% (12,3))
 print("PI is %6.3f"%3.14159)

Input:


 print("How old are you?")
 age = input()
 print("How tall are you?")
 height = input()
 print("How much do you weigh?")
 weight = input()
 print("So, you're %s old, %s tall and %s heavy." % (age, height, weight))
 

 name = input("What is your name?")
 print("so your name is " + name) 
 
 
 Mad Lib Game 
 print("MAD LIB GAME")
 print("Enter answers to the following prompts\n") 
 guy = input("Name of a famous man: ")
 girl = input("Name of a famous woman: ")
 food = input("Your favorite food (plural): ")
 ship = input("Name of a space ship: ")
 job = input("Name of a profession (plural): ")
 planet = input("Name of a planet: ")
 drink = input("Your favorite drink: ")
 number = input("A number from 1 to 10: ") 
 story = "\nA famous married couple, GUY and GIRL, went on\n" +
 "vacation to the planet PLANET. It took NUMBER\n" +
 "weeks to get there travelling by SHIP. They\n" +
 "enjoyed a luxurious candlelight dinner over-\n" +
 "looking a DRINK ocean while eating FOOD. But,\n" +
 "since they were both JOB, they had to cut their\n" +
 "vacation short." 
 story = story.replace("GUY", guy)
 story = story.replace("GIRL", girl)
 story = story.replace("FOOD", food)
 story = story.replace("SHIP", ship)
 story = story.replace("JOB", job)
 story = story.replace("PLANET", planet)
 story = story.replace("DRINK", drink)
 story = story.replace("NUMBER", number) 
 print(story)

List:

lists can contain any sort ofobject: numbers, strings, and even other lists.

classmates = ['Michael','Bob','Tracy','Tony','Cargo']
 len(classmates)
 classmates[0]
 classmates.append('Jason')
 classmates.insert(2,'Pony')
 classmates.pop()
 classmates.remove('Bob')
 classmates.pop(2)
 classmates.reverse()
 classmates.sort()
 classmates[2] ="Mike"
 classmates[1:3]
 classmates[:3]
 classmates[-1]
 classmates[-3:-1]
 classmates[:5:2]
 classmates[::-1]
 classmates.count('Bob')
 L = [
 ['Apple','Google','Microsoft'],
 ['Java','Python','Ruby','PHP'],
 ['Adam','Bart','Lisa']
 ]
 L[0][1] 
 [1, 2, 3] + [4, 5, 6]
 ['Ni!'] * 4
 3 in [1, 2, 3]

Dictionary:


 dict= {'Michael':95,'Bob':75,'Tracy':85}
 dict['Michael']
 dict['Jack'] =90
 dict['Jack']
 dict['Jack'] =87
 dict['Jack']
 dict.get('Jack')
 dict.pop('Michael')

Set:


 s=set([1,1,2,2,3,3])# it will delete same number
 s.add(4)
 s.add(4)
 print(s)# {1, 2, 3, 4}
 s.remove(2)
 s1 = {1,3,4}
 s2 = {1,2,5}
 s1 & s2
 s1 | s2

Logic:


 True and False
 True or False
 not True
 1!=2
 1==1
 3>=1
 3<=6

If:


 age = 3
 if age >= 18:
 print('adult')
 elif age >= 6:
 print('teenager')
 else:
 print('kid')

Loop:

names = ['Michael', 'Bob', 'Tracy']
 for name in names:
 print(name)

缩进

!/usr/bin/python

-- coding: UTF-8 --

文件名：test.py

if True:
print "Answer"
print "True"
else:
print "Answer"
# 没有严格缩进，在执行时会报错
print "False"

sum = 0
 for x in [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]:
 sum = sum + x
 print(sum)

sum = 0
 for x in range(10):
 sum = sum + x
 print(sum)

Functions:


 def my_abs(x):
 if x >= 0:
 return x
 else:
 return -x 
 def power(x, n):
 s = 1
 while n > 0:
 n -= 1
 s = s * x
 return s 
 def power(x, n=2):
 s = 1
 while n > 0:
 n = n - 1
 s = s * x
 return s
 def calc(*numbers):
 sum = 0
 for n in numbers:
 sum = sum + n * n
 return sum
 calc(1, 2)
 nums = [1, 2, 3]
 calc(*nums)

Recursion:


 def fact(n):
 if n==1:
 return 1
 return n * fact(n - 1)

Iteration:


 d = {'a': 1, 'b': 2, 'c': 3} 
 for key in d:
 print("key:" + key + "value:" + str(d[key]) + "\n")
 for character in "ABCDEFG":
 print(character)

Generator:

g = (x * x for x in range(10))
 next(g)
 next(g) 
 f = (x * x for x in range(10))
 for n in f:
 print(n)

def fib(max):
 n, a, b = 0, 0, 1
 while n < max:
 yield b
 a, b = b, a + b
 n = n + 1
 return 'done'
 g = fib(10) 
 for i in g:
 print(i)

High Order Function:

def add(a, b):
 return a + b 
 f = add
 print(f(1, 2))

Build-in Function:

map:

Map


 def f(x):
 return x * x 
 r = map(f, [1, 2, 3, 4, 5, 6, 7, 8, 9])
 print(list(r))

reduce:

from functools import reduce 
 def f(a, b):
 return a + b 
 r = reduce(f, [1, 2, 3, 4, 5, 6, 7, 8, 9]) 
 print(r)

filter:

def is_odd(n):
 return n % 2 == 1 
 list(filter(is_odd, [1, 2, 4, 5, 6, 9, 10, 15]))

sort:


 sorted([36, 5, -12, 9, -21])
 sorted([36, 5, -12, 9, -21], key=abs)
 sorted(['bob', 'about', 'Zoo', 'Credit'], key=str.lower, reverse=True)

Exception:


 s = input("Enter a number:")
 try:
 number = float(s)
 except:
 number = 0 
 answer = number * number 
 print(answer)

Module:

test.py

test2.py

OOP:


 class Student(object):
 def init(self, name, score):
 self.name = name
 self.score = score
 def print_score(self):
 print('%s: %s' % (self.name, self.score)) 
 bart = Student('Bart Simpson', 59)
 lisa = Student('Lisa Simpson', 87)
 bart.print_score()
 lisa.print_score()

Inheritance:


 class Animal(object):
 def run(self):
 print('Animal is running...')
 class Dog(Animal):
 pass
 class Cat(Animal):
 pass
 dog = Dog()
 dog.run()
 cat = Cat()
 cat.run()


 class Dog(Animal):
 def run(self):
 print('Dog is running...') 
 def eat(self):
    print('Eating meat...')
 
 dog = Dog()
 dog.run()

a = list()
 b = Animal()
 c = Dog() 
 print(isinstance(a,list))
 print(isinstance(b, Animal))
 print(isinstance(c, Dog))
 print(isinstance(c, Dog))

PYTHON BASIC