[英]Dynamic dictionary recursion in Python3
我已经为此工作了很长时间,需要一些帮助。 我正在尝试使用fakerr创建字典。 如果只是那么简单。 最初,字典是平的。 钥匙和物品。 如果键的第一个字母为'B'或'M',它将把该字符串转换为包含5个键的字典,并继续执行此操作,直到找不到以这两个字母中的任何一个开头的字母为止。 我知道,现在没有递归发生。 这就是为什么我需要帮助。 我试图找出如何正确递归而不是对深度进行硬编码。
Starting Dictionary:
{
"Marcia": "https://www.skinner.biz/categories/tags/terms.htm",
"Nicholas": "https://scott-tran.com/",
"Christopher": "https://www.ellis.com/",
"Paul": "https://lopez.com/index/",
"Jennifer": "https://www.sosa.com/wp-content/main/login.php"
}
Marcia应该扩展到这个...
Example:
"Marcia": {
"Alexander": "http://hicks.net/home.html",
"Barry": {
"Jared": "https://www.parker-robinson.com/faq.html",
"Eddie": "https://www.smith-thomas.com/",
"Ryan": "https://www.phillips.org/homepage/",
"Mary": {
"Alex": "http://www.perry.com/tags/explore/post.htm",
"Joseph": "https://www.hansen.com/main/list/list/index/",
"Alicia": "https://www.tran.biz/wp-content/explore/posts/",
"Anna": "http://lee-mclaughlin.biz/search/login/",
"Kevin": "https://blake.net/main/index/"
}
"Evan": "http://carroll.com/homepage.html"
}
"Sharon": "https://www.watson.org/categories/app/login/",
"Hayley": "https://www.parks.com/",
"William": "https://www.wyatt-ware.com/"
}
我的代码比动态代码更具手动性,因为我必须明确地知道现在字典中有很多层次,而不是动态地找出它。
这是我可以在2级深度下工作的东西,但是我想找到任何以'B'或'M'开头并对其进行操作的键。
import json
from build_a_dictionary import add_dic
from faker import Faker
dic = add_dic(10)
dic1 = {}
dic2 = {}
def build_dic(dic_len):
dic1 = {}
fake = Faker()
if len(dic1) == 0:
dic1 = add_dic(dic_len)
print(json.dumps(dic1, indent=4))
for k, v in dic1.items():
dic2[k] = add_dic(dic_len)
for key in dic2[k].keys():
for f in key:
if f == 'B' or f == 'M':
dic2[k][key] = add_dic(dic_len)
return dic2
这是我写的add_dic()中的代码:
import string, time
from faker import Faker #had to install with pip
fake = Faker()
dic = {}
dics = {}
key = ""
def add_dic(x):
dic={}
start = time.time()
if x > 690:
print("Please select a value under 690")
sys.exit()
for n in range(x):
while len(dic) < x:
key = fake.first_name()
if key in dic.keys():
break
val = fake.uri()
dic[key] = val
end = time.time()
runtime = end - start
return dic
您只是在做错事情,如果您希望它是递归的,则将该函数编写为递归函数。 本质上,它是字典的自定义(递归)映射函数。 至于您期望的字典,我不确定您是如何让Faker
每次确定性地给您同样的输出的。 这是随机的...
注意:对此没有任何“动态”,它只是一个递归映射函数。
from faker import Faker
import pprint
pp = pprint.PrettyPrinter(indent=4)
fake = Faker()
def map_val(key, val):
if key[0] == 'M' or key[0] == 'B':
names = [(fake.first_name(), fake.uri()) for i in range(5)]
return {k : map_val(k, v) for k,v in names}
else:
return val
#uncomment below to generate 5 initial names
#names = [(fake.first_name(), fake.uri()) for i in range(5)]
#initial_dict = {k : v for k,v in names}
initial_dict = {
"Marcia": "https://www.skinner.biz/categories/tags/terms.htm",
"Nicholas": "https://scott-tran.com/",
"Christopher": "https://www.ellis.com/",
"Paul": "https://lopez.com/index/",
"Jennifer": "https://www.sosa.com/wp-content/main/login.php"
}
dict_2 = {k : map_val(k,v) for k,v in initial_dict.items()}
pp.pprint(dict_2)
输出:
rpg711$ python nested_dicts.py
{ 'Christopher': 'https://www.ellis.com/',
'Jennifer': 'https://www.sosa.com/wp-content/main/login.php',
'Marcia': { 'Chelsea': 'http://francis.org/category.jsp',
'Heather': 'http://www.rodgers.com/privacy.jsp',
'Jaime': 'https://bates-molina.com/register/',
'John': 'http://www.doyle.com/author.htm',
'Kimberly': 'https://www.harris.org/homepage/'},
'Nicholas': 'https://scott-tran.com/',
'Paul': 'https://lopez.com/index/'
}
谢谢大家的帮助。 我设法弄清楚了。 现在,它可以根据需要构建动态字典或动态json。
import sys, json
from faker import Faker
fake = Faker()
def build_dic(dic_len, dic):
if isinstance(dic, (list, tuple)):
dic = dict(dic)
if isinstance(dic, dict):
for counter in range(len(dic)):
for k,v in dic.items():
if k[0] == 'B' or k[0] == "M":
update = [(fake.first_name(), fake.uri()) for i in range(5)]
update = dict(update)
dic.update({k: update})
return dic
def walk(dic):
for key, item in dic.items():
#print(type(item))
if isinstance(item, dict):
build_dic(5, item)
walk(item)
return dic
a = build_dic(10, ([(fake.first_name(), fake.uri()) for i in range(10)]))
walk(a)
print(json.dumps(a, indent=4))
递归是函数调用自身时; 设计递归函数时,牢记退出条件(即递归何时停止)很重要。
让我们考虑一个人为设计的示例,它增加一个数字直到达到某个值:
def increment_until_equal_to_or_greater_than_value(item, target):
print 'item is', item,
if item < target:
print 'incrementing'
item += 1
increment_until_equal_to_or_greater_than_value(item, target)
else:
print 'returning'
return item
increment_until_equal_to_or_greater_than_value(1, 10)
和输出
item is 1 incrementing
item is 2 incrementing
item is 3 incrementing
item is 4 incrementing
item is 5 incrementing
item is 6 incrementing
item is 7 incrementing
item is 8 incrementing
item is 9 incrementing
item is 10 returning
您可以看到我们已经在if
语句中定义了递归部分,并在else
定义了退出条件。
我整理了一个在嵌套数据结构上显示递归函数的代码段。
它不能完全解决您的问题,因此您可以通过剖析并使其适合您的用例来学习。
# our recursive method
def deep_do_something_if_string(source, something):
# if source is a dict, iterate through it's values
if isinstance(source, dict):
for v in source.itervalues():
# call this method on the value
deep_do_something_if_string(v, something)
# if source is a list, tuple or set, iterate through it's items
elif isinstance(source, (list, tuple, set)):
for v in source:
deep_do_something_if_string(v, something)
# otherwise do something with the value
else:
return something(source)
# a test something to do with the value
def print_it_out(value):
print value
# an example data structure
some_dict = {
'a': 'value a',
'b': [
{
'c': 'value c',
'd': 'value d',
},
],
'e': {
'f': 'value f',
'g': {
'h': {
'i': {
'j': 'value j'
}
}
}
}
}
deep_do_something_if_string(some_dict, print_it_out)
和输出
value a
value c
value d
value j
value f
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