[英]Networkx: Nodes as Objects OR Nodes as ID's with Dictionary Attribute Tables
就內存管理和計算速度而言,哪一個最有效?
下面的簡單測試表明,將節點內的屬性存儲為python對象要好於通過屬性表進行字典查找。 由於如何分配內存,情況是否總是這樣?
作為測試,我構造了一個簡單的示例:
class country():
def __init__(self, name, gdp):
self.name = name
self.gdp = gdp
def __repr__(self):
return str(self.name)
#Country Objects
countries = dict()
countries['AUS'] = country('AUS', 2000)
countries['USA'] = country('USA', 10000)
countries['ZWE'] = country('ZWE', 13)
#Attribute Dictionary
gdp = dict()
gdp['AUS'] = 2000
gdp['USA'] = 10000
gdp['ZWE'] = 13
建立網絡:
#Nodes as ID's
G1 = nx.Graph()
G1.add_nodes_from(countries.keys())
G1.nodes()
#Nodes as Objects
G2 = nx.Graph()
for c in countries.keys():
G2.add_node(countries[c])
G2.nodes()
在IPython中運行%timeit:
G1f()
#Lookup Data from Strings Network
def G1f():
for n in G1.nodes():
print "Node: %s" % n
print "\tGDP: %s" % gdp[n]
%timeit G1f
G1f()的輸出:
10000000 loops, best of 3: 26.4 ns per loop
G2f()
#Lookup Data from Objects
def G2f():
for n in G2.nodes():
print "Node: %s" % n.name
print "\tGDP: %s" % n.gdp
%timeit G2f
G2f()的輸出
10000000 loops, best of 3: 21.8 ns per loop
更新
G3f()[來自答案]
G3 = nx.Graph()
for c,v in gdp.items():
G3.add_node(c, gdp=v)
def G3f():
for n,d in G3.nodes(data=True):
print "Node: %s" % n
print "\tGDP: %s" % d['gdp']
G13f()的輸出:
10000 loops, best of 3: 63 µs per loop
您還可以使用以下節點屬性:
import networkx as nx
#Attribute Dictionary
gdp = dict()
gdp['AUS'] = 2000
gdp['USA'] = 10000
gdp['ZWE'] = 13
G3 = nx.Graph()
for c,v in gdp.items():
G3.add_node(c, gdp=v)
print G3.nodes(data=True)
def G3f():
for n,d in G3.nodes(data=True):
print "Node: %s" % n
print "\tGDP: %s" % d['gdp']
我不清楚測試時間是否非常重要。 除非這是一個非常大的問題(也許有一天每個人都會有自己的國家!),否則速度或內存上的差異可能不會太大。 我懷疑創建許多小型自定義對象(country())的開銷最終將占用更多的內存和時間。
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