假设我有这个:
[
{"name": "Tom", "age": 10},
{"name": "Mark", "age": 5},
{"name": "Pam", "age": 7}
]
通过搜索“Pam”作为名称,我想检索相关的字典:{name:“Pam”,年龄:7}
如何做到这一点?
假设我有这个:
[
{"name": "Tom", "age": 10},
{"name": "Mark", "age": 5},
{"name": "Pam", "age": 7}
]
通过搜索“Pam”作为名称,我想检索相关的字典:{name:“Pam”,年龄:7}
如何做到这一点?
当前回答
我会像这样创建一个字典的字典:
names = ["Tom", "Mark", "Pam"]
ages = [10, 5, 7]
my_d = {}
for i, j in zip(names, ages):
my_d[i] = {"name": i, "age": j}
或者,使用与问题中完全相同的信息:
info_list = [{"name": "Tom", "age": 10}, {"name": "Mark", "age": 5}, {"name": "Pam", "age": 7}]
my_d = {}
for d in info_list:
my_d[d["name"]] = d
然后你可以执行my_d["Pam"],得到{"name": "Pam", "age": 7}
其他回答
def dsearch(lod, **kw):
return filter(lambda i: all((i[k] == v for (k, v) in kw.items())), lod)
lod=[{'a':33, 'b':'test2', 'c':'a.ing333'},
{'a':22, 'b':'ihaha', 'c':'fbgval'},
{'a':33, 'b':'TEst1', 'c':'s.ing123'},
{'a':22, 'b':'ihaha', 'c':'dfdvbfjkv'}]
list(dsearch(lod, a=22))
[{'a': 22, 'b': 'ihaha', 'c': 'fbgval'},
{'a': 22, 'b': 'ihaha', 'c': 'dfdvbfjkv'}]
list(dsearch(lod, a=22, b='ihaha'))
[{'a': 22, 'b': 'ihaha', 'c': 'fbgval'},
{'a': 22, 'b': 'ihaha', 'c': 'dfdvbfjkv'}]
list(dsearch(lod, a=22, c='fbgval'))
[{'a': 22, 'b': 'ihaha', 'c': 'fbgval'}]
你必须遍历列表中的所有元素。没有捷径!
除非在其他地方保存了一个包含指向列表项的名称的字典,但这时必须处理从列表中弹出元素的后果。
我会像这样创建一个字典的字典:
names = ["Tom", "Mark", "Pam"]
ages = [10, 5, 7]
my_d = {}
for i, j in zip(names, ages):
my_d[i] = {"name": i, "age": j}
或者,使用与问题中完全相同的信息:
info_list = [{"name": "Tom", "age": 10}, {"name": "Mark", "age": 5}, {"name": "Pam", "age": 7}]
my_d = {}
for d in info_list:
my_d[d["name"]] = d
然后你可以执行my_d["Pam"],得到{"name": "Pam", "age": 7}
我测试了各种方法来遍历字典列表并返回键x具有特定值的字典。
结果:
速度:列表推导>生成器表达式>>常规列表迭代>>>过滤器。 所有的比例都与列表中的字典数量线性(10x列表大小-> 10x时间)。 对于大量(数千个)键,每个字典的键不会显著影响速度。请看我计算的图表:https://imgur.com/a/quQzv(方法名称见下文)。
所有测试均使用Python 3.6.4, W7x64完成。
from random import randint
from timeit import timeit
list_dicts = []
for _ in range(1000): # number of dicts in the list
dict_tmp = {}
for i in range(10): # number of keys for each dict
dict_tmp[f"key{i}"] = randint(0,50)
list_dicts.append( dict_tmp )
def a():
# normal iteration over all elements
for dict_ in list_dicts:
if dict_["key3"] == 20:
pass
def b():
# use 'generator'
for dict_ in (x for x in list_dicts if x["key3"] == 20):
pass
def c():
# use 'list'
for dict_ in [x for x in list_dicts if x["key3"] == 20]:
pass
def d():
# use 'filter'
for dict_ in filter(lambda x: x['key3'] == 20, list_dicts):
pass
结果:
1.7303 # normal list iteration
1.3849 # generator expression
1.3158 # list comprehension
7.7848 # filter
people = [
{'name': "Tom", 'age': 10},
{'name': "Mark", 'age': 5},
{'name': "Pam", 'age': 7}
]
def search(name):
for p in people:
if p['name'] == name:
return p
search("Pam")