我已经使用python一段时间了，并且做了一些改进，但这对我来说是一个新的错误。我正在尝试学习职业生涯中的社交媒体分析，这就是为什么我尝试了这组代码here。
我已经调试了一个错误，但是出现在第81行的这个错误使我感到困惑，因为我看不到为什么函数“ def get_user_objects（follower_ids）：”不返回任何值，而我需要根据此处其他问题的先前建议进行更改。
为简单起见，这里有脚本。感谢所有帮助。
要重复的错误是TypeError：类型为'NoneType'的对象没有len（）
from tweepy import OAuthHandler
from tweepy import API
from collections import Counter
from datetime import datetime, date, time, timedelta
import sys
import json
import os
import io
import re
import time
# Helper functions to load and save intermediate steps
def save_json(variable, filename):
with io.open(filename, "w", encoding="utf-8") as f:
f.write(str(json.dumps(variable, indent=4, ensure_ascii=False)))
def load_json(filename):
ret = None
if os.path.exists(filename):
try:
with io.open(filename, "r", encoding="utf-8") as f:
ret = json.load(f)
except:
pass
return ret
def try_load_or_process(filename, processor_fn, function_arg):
load_fn = None
save_fn = None
if filename.endswith("json"):
load_fn = load_json
save_fn = save_json
else:
load_fn = load_bin
save_fn = save_bin
if os.path.exists(filename):
print("Loading " + filename)
return load_fn(filename)
else:
ret = processor_fn(function_arg)
print("Saving " + filename)
save_fn(ret, filename)
return ret
# Some helper functions to convert between different time formats and
perform date calculations
def twitter_time_to_object(time_string):
twitter_format = "%a %b %d %H:%M:%S %Y"
match_expression = "^(.+)\s(\+[0-9][0-9][0-9][0-9])\s([0-9][0-9][0-9]
[09])$"
match = re.search(match_expression, time_string)
if match is not None:
first_bit = match.group(1)
second_bit = match.group(2)
last_bit = match.group(3)
new_string = first_bit + " " + last_bit
date_object = datetime.strptime(new_string, twitter_format)
return date_object
def time_object_to_unix(time_object):
return int(time_object.strftime("%s"))
def twitter_time_to_unix(time_string):
return time_object_to_unix(twitter_time_to_object(time_string))
def seconds_since_twitter_time(time_string):
input_time_unix = int(twitter_time_to_unix(time_string))
current_time_unix = int(get_utc_unix_time())
return current_time_unix - input_time_unix
def get_utc_unix_time():
dts = datetime.utcnow()
return time.mktime(dts.timetuple())
# Get a list of follower ids for the target account
def get_follower_ids(target):
return auth_api.followers_ids(target)
# Twitter API allows us to batch query 100 accounts at a time
# So we'll create batches of 100 follower ids and gather Twitter User
objects for each batch
def get_user_objects(follower_ids):
batch_len = 100
num_batches = len(follower_ids)/100
batches = (follower_ids[i:i+batch_len] for i in range(0,
len(follower_ids), batch_len))
all_data = []
for batch_count, batch in enumerate(batches):
sys.stdout.write("\r")
sys.stdout.flush()
sys.stdout.write("Fetching batch: " + str(batch_count) + "/" +
str(num_batches))
sys.stdout.flush()
users_list = auth_api.lookup_users(user_ids=batch)
users_json = (map(lambda t: t._json, users_list))
all_data += users_json
return all_data
# Creates one week length ranges and finds items that fit into those range
boundaries
def make_ranges(user_data, num_ranges=20):
range_max = 604800 * num_ranges
range_step = range_max/num_ranges
# We create ranges and labels first and then iterate these when going
through the whole list
# of user data, to speed things up
ranges = {}
labels = {}
for x in range(num_ranges):
start_range = x * range_step
end_range = x * range_step + range_step
label = "%02d" % x + " - " + "%02d" % (x+1) + " weeks"
labels[label] = []
ranges[label] = {}
ranges[label]["start"] = start_range
ranges[label]["end"] = end_range
for user in user_data:
if "created_at" in user:
account_age = seconds_since_twitter_time(user["created_at"])
for label, timestamps in ranges.iteritems():
if account_age > timestamps["start"] and account_age <
timestamps["end"]:
entry = {}
id_str = user["id_str"]
entry[id_str] = {}
fields = ["screen_name", "name", "created_at",
"friends_count", "followers_count", "favourites_count", "statuses_count"]
for f in fields:
if f in user:
entry[id_str][f] = user[f]
labels[label].append(entry)
return labels
if __name__ == "__main__":
account_list = []
if (len(sys.argv) > 1):
account_list = sys.argv[1:]
if len(account_list) < 1:
print("No parameters supplied. Exiting.")
sys.exit(0)
consumer_key="XXXXXXX"
consumer_secret="XXXXXX"
access_token="XXXXXXX"
access_token_secret="XXXXXXXX"
auth = OAuthHandler(consumer_key, consumer_secret)
auth.set_access_token(access_token, access_token_secret)
auth_api = API(auth)
for target in account_list:
print("Processing target: " + target)
# Get a list of Twitter ids for followers of target account and save it
filename = target + "_follower_ids.json"
follower_ids = try_load_or_process(filename, get_follower_ids,
target)
# Fetch Twitter User objects from each Twitter id found and save the data
filename = target + "_followers.json"
user_objects = try_load_or_process(filename, get_user_objects,
follower_ids)
total_objects = len(user_objects)
# Record a few details about each account that falls between specified age
ranges
ranges = make_ranges(user_objects)
filename = target + "_ranges.json"
save_json(ranges, filename)
# Print a few summaries
print
print("\t\tFollower age ranges")
print("\t\t===================")
total = 0
following_counter = Counter()
for label, entries in sorted(ranges.iteritems()):
print("\t\t" + str(len(entries)) + " accounts were created
within " + label)
total += len(entries)
for entry in entries:
for id_str, values in entry.iteritems():
if "friends_count" in values:
following_counter[values["friends_count"]] += 1
print("\t\tTotal: " + str(total) + "/" + str(total_objects))
print
print("\t\tMost common friends counts")
print("\t\t==========================")
total = 0
for num, count in following_counter.most_common(20):
total += count
print("\t\t" + str(count) + " accounts are following " +
str(num) + " accounts")
print("\t\tTotal: " + str(total) + "/" + str(total_objects))
print
print
答案 0 :(得分：1)
直接的问题出在load_json中：您假设其返回值是列表或字典，或者可以传递给len的东西。但是，在许多情况下，它可以返回None：
null。调用load_json之后，您将不会检查其返回值。
更糟糕的是，您捕获并忽略了load_json中可能发生的任何异常，从而导致该异常以静默方式返回None，而没有迹象表明出现了问题。
函数最好写成这样
def load_json(filename):
with io.open(filename, "r", encoding="utf-8") as f:
return json.load(f)
至少现在，任何错误都将引发未捕获的异常，这使问题更加明显，并提供了有关问题根源的线索。异常处理的黄金法则是只捕获可以做的异常，如果对捕获的异常不能做任何事情，请重新引发。
答案 1 :(得分：0)
您可以检查结果值并相应地进行操作：
# Fetch Twitter User objects from each Twitter id found and save the data
filename = target + "_followers.json"
res_get_user_objects = get_user_objects()
if res_get_user_objects is not None:
user_objects = try_load_or_process(filename, get_user_objects,
follower_ids)
total_objects = len(user_objects)
else:
# handle it otherwise