参考链接：https://www.numpy.org.cn/article/basics/python_numpy_tutorial.html
（1）Numbers（数字类型）
x = 3 print(type(x)) # Prints "<class 'int'>" print(x) # Prints "3" print(x + 1) # Addition; prints "4" print(x - 1) # Subtraction; prints "2" print(x * 2) # Multiplication; prints "6" print(x ** 2) # Exponentiation; prints "9" x += 1 print(x) # Prints "4" x *= 2 print(x) # Prints "8" y = 2.5 print(type(y)) # Prints "<class 'float'>" print(y, y + 1, y * 2, y ** 2) # Prints "2.5 3.5 5.0 6.25"（2）Booleans（布尔类型） Python实现了所有常用的布尔逻辑运算符，但它使用的是英文单词而不是符号 (&&, ||, etc.)：
t = True f = False print(type(t)) # Prints "<class 'bool'>" print(t and f) # Logical AND; prints "False" print(t or f) # Logical OR; prints "True" print(not t) # Logical NOT; prints "False" print(t != f) # Logical XOR; prints "True"（3）String（字符串类型）
hello = 'hello' # String literals can use single quotes world = "world" # or double quotes; it does not matter. print(hello) # Prints "hello" print(len(hello)) # String length; prints "5" #字符串连接 hw = hello + ' ' + world # String concatenation print(hw) # prints "hello world" #格式化 hw12 = '%s %s %d' % (hello, world, 12) # sprintf style string formatting print(hw12) # prints "hello world 12"String对象有许多有用的方法；例如：
s = "hello" print(s.capitalize()) # Capitalize a string; prints "Hello" print(s.upper()) # Convert a string to uppercase; prints "HELLO" print(s.rjust(7)) # Right-justify a string, padding with spaces; prints " hello" print(s.center(7)) # Center a string, padding with spaces; prints " hello " print(s.replace('l', '(ell)')) # Replace all instances of one substring with another; # prints "he(ell)(ell)o" print(' world '.strip()) # Strip leading and trailing whitespace; prints "world"在此链接中可找到所有关于字符串的方法https://docs.python.org/3.5/library/stdtypes.html#string-methods
Python包含几种内置的容器类型：列表、字典、集合和元组。 （1）列表 列表其实就是Python中的数组，但是可以它可以动态的调整大小并且可以包含不同类型的元素：
xs = [3, 1, 2] # Create a list print(xs, xs[2]) # Prints "[3, 1, 2] 2" print(xs[-1]) # Negative indices count from the end of the list; prints "2" xs[2] = 'foo' # Lists can contain elements of different types print(xs) # Prints "[3, 1, 'foo']" xs.append('bar') # Add a new element to the end of the list print(xs) # Prints "[3, 1, 'foo', 'bar']" x = xs.pop() # Remove and return the last element of the list print(x, xs) # Prints "bar [3, 1, 'foo']"切片：除了一次访问一个列表元素之外，Python还提供了访问子列表的简明语法; 这被称为切片：
#list(rang(number))代码中非常常见，range(5)并不是一个列表，只是表示范围。与np中arange()不同。 nums = list(range(5)) # range is a built-in function that creates a list of integers print(nums) # Prints "[0, 1, 2, 3, 4]" print(nums[2:4]) # Get a slice from index 2 to 4 (exclusive); prints "[2, 3]" print(nums[2:]) # Get a slice from index 2 to the end; prints "[2, 3, 4]" print(nums[:2]) # Get a slice from the start to index 2 (exclusive); prints "[0, 1]" print(nums[:]) # Get a slice of the whole list; prints "[0, 1, 2, 3, 4]" print(nums[:-1]) # Slice indices can be negative; prints "[0, 1, 2, 3]" nums[2:4] = [8, 9] # Assign a new sublist to a slice print(nums) # Prints "[0, 1, 8, 9, 4]"我们将在numpy数组的上下文中再次看到切片。 循环：可以循环遍历列表的元素，如下所示：
animals = ['cat', 'dog', 'monkey'] for animal in animals: print(animal) # Prints "cat", "dog", "monkey", each on its own line.非常重要：如果要访问循环体内每个元素的索引，请使用内置的 enumerate 函数：
animals = ['cat', 'dog', 'monkey'] for idx, animal in enumerate(animals): print('#%d: %s' % (idx + 1, animal)) # Prints "#1: cat", "#2: dog", "#3: monkey", each on its own line列表推导式：编程时，我们经常想要将一种数据转换为另一种数据。 举个简单的例子，思考以下计算平方数的代码：
nums = [0, 1, 2, 3, 4] squares = [] for x in nums: squares.append(x ** 2) print(squares) # Prints [0, 1, 4, 9, 16]你可以使用 列表推导式 使这段代码更简单:
nums = [0, 1, 2, 3, 4] squares = [x ** 2 for x in nums] print(squares) # Prints [0, 1, 4, 9, 16]列表推导还可以包含条件：
nums = [0, 1, 2, 3, 4] even_squares = [x ** 2 for x in nums if x % 2 == 0] print(even_squares) # Prints "[0, 4, 16]"（2）字典
字典存储（键，值）对，类似于Java中的Map或Javascript中的对象。你可以像这样使用它：
d = {'cat': 'cute', 'dog': 'furry'} # Create a new dictionary with some data print(d['cat']) # Get an entry from a dictionary; prints "cute" print('cat' in d) # Check if a dictionary has a given key; prints "True" d['fish'] = 'wet' # Set an entry in a dictionary print(d['fish']) # Prints "wet" # print(d['monkey']) # KeyError: 'monkey' not a key of d print(d.get('monkey', 'N/A')) # Get an element with a default; prints "N/A" print(d.get('fish', 'N/A')) # Get an element with a default; prints "wet" del d['fish'] # Remove an element from a dictionary print(d.get('fish', 'N/A')) # "fish" is no longer a key; prints "N/A"循环：迭代词典中的键很容易：
d = {'person': 2, 'cat': 4, 'spider': 8} #遍历字典中的键 for animal in d: legs = d[animal] print('A %s has %d legs' % (animal, legs)) # Prints "A person has 2 legs", "A cat has 4 legs", "A spider has 8 legs"如果要访问键及其对应的值，请使用items方法：
d = {'person': 2, 'cat': 4, 'spider': 8} for animal, legs in d.items(): print('A %s has %d legs' % (animal, legs)) # Prints "A person has 2 legs", "A cat has 4 legs", "A spider has 8 legs"字典推导式：类似于列表推导式，可以让你轻松构建词典数据类型。例如：
nums = [0, 1, 2, 3, 4] even_num_to_square = {x: x ** 2 for x in nums if x % 2 == 0} print(even_num_to_square) # Prints "{0: 0, 2: 4, 4: 16}"（3）集合 集合是不同元素的无序集合。举个简单的例子，请思考下面的代码：
animals = {'cat', 'dog'} print('cat' in animals) # Check if an element is in a set; prints "True" print('fish' in animals) # prints "False" animals.add('fish') # Add an element to a set print('fish' in animals) # Prints "True" print(len(animals)) # Number of elements in a set; prints "3" animals.add('cat') # Adding an element that is already in the set does nothing print(len(animals)) # Prints "3" animals.remove('cat') # Remove an element from a set print(len(animals)) # Prints "2"循环：遍历集合的语法与遍历列表的语法相同；但是，由于集合是无序的，因此不能假设访问集合元素的顺序
animals = {'cat', 'dog', 'fish'} for idx, animal in enumerate(animals): print('#%d: %s' % (idx + 1, animal)) # Prints "#1: fish", "#2: dog", "#3: cat"集合推导式：就像列表和字典一样，我们可以很容易地使用集合理解来构造集合：
from math import sqrt nums = {int(sqrt(x)) for x in range(30)} print(nums) # Prints "{0, 1, 2, 3, 4, 5}"（4）元组 元组是（不可变的）有序值列表。 元组在很多方面类似于列表; 其中一个最重要的区别是元组可以用作字典中的键和集合的元素，而列表则不能。 这是一个简单的例子：
d = {(x, x + 1): x for x in range(10)} # Create a dictionary with tuple keys t = (5, 6) # Create a tuple print(type(t)) # Prints "<class 'tuple'>" print(d[t]) # Prints "5" print(d[(1, 2)]) # Prints "1"Python函数使用def关键字定义。例如：
def sign(x): if x > 0: return 'positive' elif x < 0: return 'negative' else: return 'zero' for x in [-1, 0, 1]: print(sign(x)) # Prints "negative", "zero", "positive"我们经常定义函数来获取可选的关键字参数，在项目代码中也经常使用，先给参数指定一个默认值，以防万一。如下所示：
def hello(name, loud=False): if loud: print('HELLO, %s!' % name.upper()) else: print('Hello, %s' % name) hello('Bob') # Prints "Hello, Bob" hello('Fred', loud=True) # Prints "HELLO, FRED!"在Python中定义类的语法很简单：
class Greeter(object): # Constructor def __init__(self, name): self.name = name # Create an instance variable # Instance method def greet(self, loud=False): if loud: print('HELLO, %s!' % self.name.upper()) else: print('Hello, %s' % self.name) g = Greeter('Fred') # Construct an instance of the Greeter class g.greet() # Call an instance method; prints "Hello, Fred" g.greet(loud=True) # Call an instance method; prints "HELLO, FRED!"