python語言之字典dict簡析

1.基本的增刪改查

def test_1():
# 增刪改查
dict1 = {'a': 1, 'b': 2}
dict1['c'] = 3
assert {'a': 1, 'b': 2, 'c': 3} == dict1, 'dict 新增失敗'

del dict1['b']
assert {'a': 1, 'c': 3} == dict1, 'dict 刪除失敗'
dict1['c'] = 4
assert {'a': 1, 'c': 4} == dict1, 'dict 修改失敗'

c = dict1['c']
assert 4 == c, 'dict 查詢失敗'
pass

2. in和enumerate方法

def test_2():
# in, enumerate
dict1 = {'a': 1, 'b': 2}
indexs = [i for i, v in enumerate(dict1.items()) if v[0] == 'b']
assert [1] == indexs, 'dict enumerate error'

assert 'a' in dict1, 'dict in error'
pass

3.方法: setdefault,update,get,pop,popitem

def test_3():
# setdefault,update,get,pop,popitem
# setdefault 如果沒有則增加，有則不變
dict1 = {'a': 1, 'b': 2}
dict1.setdefault('c', 4)
assert {'a': 1, 'b': 2, 'c': 4}, 'dict setdefault error'

dict1.setdefault('b', 1)
assert {'a': 1, 'b': 2, 'c': 4} == dict1, 'dict setdefault b error'

dict1.update({'c': 5})
assert {'a': 1, 'b': 2, 'c': 5} == dict1, 'dict update error'

c = dict1.get('c', 1)
assert 5 == c, 'dict get error'

f = dict1.get('f', 1)
assert 1 == f, 'dict get f error'

dict1.pop('c')
assert {'a': 1, 'b': 2} == dict1, 'dict pop error'

dict1.popitem()
assert {'a': 1} == dict1, 'dict popitem error'

pass

4. sort

def test_4():
# sort
dict1 = {'b': 2, 'a': 1}
dict2 = dict(sorted(dict1.items(), key=lambda kv: kv[0]))
assert {'a': 1, 'b': 2} == dict2, 'dict sorted 1 error'

dict1 = {'b': 2, 'a': 1, 'c': 1}
dict2 = dict(sorted(dict1.items(), key=lambda kv: (kv[1], kv[0])))
assert {'a': 1, 'c': 1, 'b': 2}

pass

5.淺復制和深復制

import copy

def test_5():
# 淺復制 和 深度復制
# 1.淺復制：不改變原字典
dict1 = {'a': 1, 'b': 2}
dict2 = dict1.copy()
dict2.update({'b': 1})
assert {'a': 1, 'b': 2} == dict1, 'dict copy 1 error'
assert {'a': 1, 'b': 1} == dict2, 'dict copy 1.1 error'

# 2.淺復制：改變原字典--子對象
dict1 = {'a': 1, 'b': {'c': 1}}
dict2 = dict1.copy()
dict2['b'].setdefault('d', 2)
assert {'a': 1, 'b': {'c': 1, 'd': 2}} == dict1, 'dict copy 2 error'
assert {'a': 1, 'b': {'c': 1, 'd': 2}} == dict2, 'dict copy 2.1 error'

# 3.深復制：不改變原字典
dict1 = {'a': 1, 'b': {'c': 1}}
dict2 = copy.deepcopy(dict1)
dict2['b'].setdefault('d', 2)
assert {'a': 1, 'b': {'c': 1}} == dict1, 'dict copy 3 error'
assert {'a': 1, 'b': {'c': 1, 'd': 2}} == dict2, 'dict copy 3.1 error'

pass

6.dict的各種初始化

def test_6():
# 方法：dict(p)

dict1 = {}
assert {} == dict1, 'dict new 1 error'

dict1 = dict()
assert {} == dict1, 'dict new 2 error'

dict1 = dict({'a': 1})
assert {'a': 1} == dict1, 'dict new 3 error'

dict1 = dict([('a', 1), ('b', 2)])
assert {'a': 1, 'b': 2} == dict1, 'dict new 4 error'

dict1 = dict(a=1, b=2)
assert {'a': 1, 'b': 2} == dict1, 'dict new 5 error'

params = {'a': 1, 'b': 2}
dict1 = dict(**params)
assert {'a': 1, 'b': 2} == dict1, 'dict new 6 error'
pass



審核編輯：劉清