介绍
本篇博文主要是对自己在使用Python过程对这些基础数据结构的常见用法的总结，主要目的是能够方便自己在编写Python程序时，能够随时查看这篇笔记，从而实现快速查询不同基础数据结构基本用法的作用，也希望对大家有所帮助。
list列表
列表创建：
（1）简单创建
x = [1,2,3]
x = [1,"name",10.0]
x = list(range(10))
（2）列表理解（list comprehension）
nums = [0, 1, 2, 3, 4]
squares = [x ** 2 for x in nums]
print(squares) # Prints [0, 1, 4, 9, 16]
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]"
列表切片(slicing)：
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]"
列表遍历：
（1）纯元素遍历
animals = ['cat', 'dog', 'monkey']
for animal in animals:
print(animal)
# Prints "cat", "dog", "monkey", each on its own line.
（2）带索引遍历
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
tuple元组
1、对元组中每个元素乘以一个倍数
d = (2, 3)
print(d)
y = tuple(map(lambda x: x*2, d))
print(y)
字典
字典创建：
（1）直接创建
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"
（2）字典推导式
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}"
字典遍历：
（1）直接遍历
得到的是键
d = {'person': 2, 'cat': 4, 'spider': 8}
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"
（2）利用字典成员函数
items成员函数返回键值对元组
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"
keys成员函数返回键：
d = {'person': 2, 'cat': 4, 'spider': 8}
for animal in d.keys():
print('A %s' % (animal))
# Prints "A person has 2 legs", "A cat has 4 legs", "A spider has 8 legs"
values成员函数返回值：
d = {'person': 2, 'cat': 4, 'spider': 8}
for animal in d.values():
print('A %s' % (animal))
字符串
字符串格式化
id_text = '{} {:.2f}'.format(10, 3.1415926)
print(id_text)
注意如何限定小数点位数。
【参考】
1、https://cs231n.github.io/python-numpy-tutorial/
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