我使用下面的python代码来度量将元素附加到大型列表字典中的效率。字典中有N词条。每个条目都是M整数的列表。因此,我假设所占用的内存是关于N * M * 4bytes的。如果N是100万,M是300,那么1M * 300 * 4bytes,也就是1.2G。但令我惊讶的是,python的sys.getsizeof只报告了40兆字节的内存消耗。我哪里做错了?
import sys
import time
N=1000000
M=300
start = time.time()
d={}
for n in range(N):
d[n]=[]
for m in range(M):
known = {0:0, 1:1}
def fibonacci(n):
if n in known:
return known[n]
result = fibonacci(n-1) + fibonacci(n-2)
known[n] = result
return result
print(fibonacci(4))
那么,这本字典(记忆版)是怎么写的呢?序列有效吗?我想#每当我们调用一个新参数(之前没有调用),计算就需要一些时间,就像递归版本所做的那样。但它只会立即输出结果。这是否意味着所有的fibo。结果存储在python程序本
我有一个JSON File(),它看起来像这样。 [{
"query": "In China Cash flow from operating activities was $670 million, up 19%.ABB's regional and country order trends for the third quarter are illustrated on Slide 4.",
"topScoringIntent": {
"intent": "Operating environment&
我对python相当陌生,我已经被你们中许多人可能会发现的“小菜一碟”所挑战。产出必须是:
The Monkey-child could not fall asleep, so the mother told him a story, he was once a Tiger-child
The Tiger-child could not fall asleep, so the mother told him a story, he was once a Human-child
The Human-child could not fall asleep, so the mother
我试图递归地计算路径中python文件和非python文件的数量。
import os
def main():
#path = input('Enter an existing path to a file or directory: ')
path ='/Users/ziyuanhan/PycharmProjects/lab6/'
print(count_file(path, counter={'py':0, 'non_py':0}))
def count_file(path,counter):
下面是一个函数(归功于用户Abbot,在另一个问题中提供了它)
def traverse(ftp):
level = {}
for entry in (path for path in ftp.nlst() if path not in ('.', '..')):
ftp.cwd(entry)
level[entry] = traverse(ftp)
ftp.cwd('..')
return level
下面是我不理解的地方:当python进入函数时,它会创建一个空字典(
我偶然发现了这样一个函数,它可以把字典压平:
def flatten(dictionnary, container=None):
if container is None:
container = []
for k, v in dictionnary.items():
container.append(k)
if v:
flatten(v, container)
return container
为了测试它,我创建了一个字典,它是嵌套的n时间,如下所示:
nesteddict = {}
for i
我从一个客户那里发来了一些cookie,让我可以通过编程登录到他的服务器上,而不需要凭据。
我正在使用requests包向他的服务器发出HTTP请求。问题是他发送的cookie都是JSON格式的,我似乎找不到任何方法来加载这些cookie。
除了编写方法将它们转换为常规cookie之外,是否有任何现有的解决方案来加载这些cookie?
下面是我当前的代码:
def cookieLogin(cookies):
with open(cookies) as f:
cookies = requests.utils.cookiejar_from_dict(json.load(f
我有一个python的递归方法问题,代码是这样的:
class NodeTree(object):
def __init__(self, name, children):
self.name = name
self.children = children
def count(self):
# 1 + i children's nodes
count = 1
for c in self.children:
count += c.count()
retu