赋值前引用的局部变量'data' - Python

Question

我的代码中出现错误

请求方法： GET
请求网址： http://localhost:8000/emotion/
Django 版本： 2.2
异常类型： UnboundLocalError
Exception Value：
赋值前引用的局部变量 'data'
Exception Location： C：\Users\Sant\

Desktop\music_demo\music_site\views.py 在情感中，第 314 行
Python 可执行文件： C：\Users\Sant\AppData\Local\Programs\Python\Python37-32\python.exe
Python 版本： 3.7.3
Python Path：
['C：\Users\Sant\Desktop\music_demo'，

服务器时间：2019 年 6 月 16 日星期日 17：27：51 +0000

法典：

def emotion(request):
from mutagen.id3 import ID3
from mutagen.mp3 import MP3
import sys
import spotipy
from spotipy.oauth2 import SpotifyClientCredentials
client_id = '26473c91fefc43eca3a6531e0f062723'
client_secret = '9d7c8ddb18594838ae5db6ad10b3ddf0'
title = 'lollypop'
artist = 'pawan singh'
client_credentials_manager = SpotifyClientCredentials(client_id=client_id, client_secret=client_secret)
sp = spotipy.Spotify(client_credentials_manager=client_credentials_manager)
sp.trace=False
search_query = title+ ' ' + artist
result = sp.search(search_query)
for i in result['tracks']['items']:
# Find a songh that matches title and artist
if (i['artists'][0]['name'] == artist) and (i['name'] == title):
print (i['uri'])
break
else:
try:
# Just take the first song returned by the search (might be named differently)
print (result['tracks']['items'][0]['uri'])
uri = result['tracks']['items'][0]['uri']
client_credentials_manager = SpotifyClientCredentials(client_id=client_id, client_secret=client_secret)
sp = spotipy.Spotify(client_credentials_manager=client_credentials_manager)
sp.trace=False
features = sp.audio_features(uri)
print ('Energy:', features[0]['energy'])
data = {
"energy" :  features[0]["energy"],
"valence" : features[0]["valence"],
"key" : features[0]["key"],
"link" : features[0]["valence"],
"danceability" : features[0]["link"],
"loudness" : features[0]["loudness"],
"tempo" : features[0]["tempo"],
"acousticness" : features[0]["acousticness"],
"liveness" : features[0]["liveness"],
"instrumentalness" : features[0]["instrumentalness"]
}
except:
# No results for artist and title
print ("Cannot Find URI")
# return HttpResponse(features[0]['energy'])
return render(request, 'music_site/emotion.html', data) # Error is raised because of data dictionary

Answer 1

如果在行之前的try/except块中发生异常：

`data = {` 

那么data永远不会被设置。

您需要在except子句中或try语句之前将其设置为默认值(例如 None)。