分配前引用的局部变量“数据” - python答案

【问题标题】：local variable 'data' referenced before assignment - python分配前引用的局部变量“数据” - python
【发布时间】：2019-10-30 10:45:09
【问题描述】：

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
异常值：
赋值前引用的局部变量“数据”
异常位置：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 路径：
['C:\Users\Sant\Desktop\music_demo',

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

代码：

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

【问题讨论】：

在except的情况下，它没有设置data，因此你使用了data变量，但是你之前没有设置它。
非常感谢，我是 python 的新手 :)

标签： python django

【解决方案1】：

如果在行前的try/except块中发生异常：

`data = {`

那么data 将永远不会被设置。

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）。

【讨论】：