Python Numpy Tutorial: 字典

# -*- coding: utf-8 -*-
"""
Python Version: 3.5
Created on Mon May  8 16:02:30 2017
E-mail: Eric2014_Lv@sjtu.edu.cn
@author: DidiLv
"""

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.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"

print("-------------------------------------------")
d = {'person': 2, 'cat': 4, 'spider': 8}
# method 1:
for animal in d:
legs = d[animal]
print('A %s has %d legs' % (animal, legs))
# method 2: by using iteritems to find key and values
for animal, legs in d.items():
print('A %s has %d legs' % (animal, legs))

# Note：In python 3.5, the dictionary has no iteritems term, they are iters())

# 字典解析 类似于列表解析 功能强大
dict_1 = {animal: legs for animal, legs in d.items()}
print(dict_1)