我正在尝试将节点批量导入 Neo4j。但是当我尝试执行它时，它会抛出一个错误：List indices must be integers, not float. 我真的不明白哪些列表项，我确实有浮动，但这些被转换为字符串......
部分代码：
graph_db = neo4j.GraphDatabaseService("http://127.0.0.1:7474/db/data/")
batch = neo4j.WriteBatch(graph_db)
for ngram, one_grams in data.items():
ngram_rank = int(one_grams['_rank'])
ngram_prob = '%.16f' % float(one_grams['_prob'])
ngram_id = 'a'+str(n)
ngram_node = batch.create(node({"word": ngram, "rank": str(ngram_rank), "prob": str(ngram_prob)}))
for one_gram, two_grams in one_grams.items():
one_rank = int(two_grams['_rank'])
one_prob = '%.16f' % float(two_grams['_prob'])
one_node = batch.create(node({"word": one_gram, "rank": str(one_rank), "prob": one_prob}))
batch.create(rel((ngram_node, "FOLLOWED_BY", one_node))) #line 81 throwing error
results = batch.submit()
完整回溯
Traceback (most recent call last):
File "Ngram_neo4j.py", line 81, in probability_items
batch.create(rel((ngram_node, "FOLLOWED_BY", one_node))),
File "virtenv\\lib\\site-packages\\py2neo\\neo4j.py", line 2692, in create
uri = self._uri_for(entity.start_node, "relationships"),
File "virtenv\\lib\\site-packages\\py2neo\\neo4j.py", line 2537, in _uri_for
uri = "{{{0}}}".format(self.find(resource)),
File "virtenv\\lib\\site-packages\\py2neo\\neo4j.py", line 2525, in find
for i, req in pendulate(self._requests):,
File "virtenv\\lib\\site-packages\\py2neo\\util.py", line 161, in pendulate
yield index, collection[index],
TypeError: list indices must be integers, not float
运行 neo4j 2.0、py2neo 1.6.1、Windows 7/64bit、python 3.3/64bit
- 编辑 -
做了一些测试，但错误位于对节点的引用。过度简化的示例代码：
for key, dict in data.items(): #string, dictionary
batch = neo4j.WriteBatch(graph_db)
three_gram_node = batch.create(node({"word": key}))
pprint(three_gram_node)
batch.add_labels(three_gram_node, "3gram") # must be int, not float
for k,v in dict.items(): #string, string
four_gram_node = batch.create(node({"word": k}))
batch.create_path(three_gram_node, "FOLLOWED_BY", four_gram_node)
# cannot cast node from BatchRequest obj
batch.submit()
创建节点时batch.create(node({props}))，pprint返回一个P2Neo.neo4j. batchrequest object. 在该行add_labels()，它给出了与尝试创建关系时相同的错误：List indices must be integers, not float。在该batch.create_path()行它会抛出一个错误，说它不能从P2Neo.neo4j. batchrequest object.
我现在正在尝试脏调试以了解索引。
--脏调试编辑--
我一直在玩弄这个pendulate(collection) 功能。虽然我不太明白它是如何适应的，以及它是如何使用的，但会发生以下情况：每当它遇到一个奇数时，它就会被转换为一个浮点数（这很奇怪，因为count - ((i + 1) / 2)，哪里i是一个奇数。）这个float 然后抛出list indices错误。一些印刷品：
count: 3
i= 0
index: 0
(int)index: 0
i= 1 # i = uneven
index: 2.0 # a float appears
(int)index: 2 # this is a safe cast
这会导致list indices错误。这也发生在i=0. 由于这是一种常见情况，我做了一个额外if()的代码来规避代码（可能的加速？）虽然我没有对此进行单元测试，但似乎我们可以安全地将 index 转换为 int ...
使用的 pendulate 函数：
def pendulate(collection):
count = len(collection)
print("count: ", count)
for i in range(count):
print("i=", i)
if i == 0:
index = 0
elif i % 2 == 0:
index = i / 2
else:
index = count - ((i + 1) / 2)
print("index:", index)
index = int(index)
print("(int)index:", index)
yield index, collection[index]