<p>哦,您必须设置一个条件来检查<code><DATE></code>键。只有这个加法才能得到预期的输出</p>
<p><strong>您的输入列表</strong></p>
<pre><code>dict_list = [{'<TICKER>': 'HDR', '<DATE>': '19980317', '<CLOSE>': '11.633', '<VOL>': '67931'}, {'<TICKER>': 'HDR', '<DATE>': '19980318', '<CLOSE>': '10.481', '<VOL>': '115169'}, {'<TICKER>': 'HDR', '<DATE>': '19980319', '<CLOSE>': '10.131', '<VOL>': '75305'}, {'<TICKER>': 'HDR', '<DATE>': '19980320', '<CLOSE>': '10.481', '<VOL>': '53504'}, {'<TICKER>': 'HDR', '<DATE>': '19980323', '<CLOSE>': '10.379', '<VOL>': '27581'}, {'<TICKER>': 'HDR', '<DATE>': '19980324', '<CLOSE>': '10.228', '<VOL>': '37328'}, {'<TICKER>': 'HDR', '<DATE>': '19980325', '<CLOSE>': '10.131', '<VOL>': '28739'}, {'<TICKER>': 'HDR', '<DATE>': '19980326', '<CLOSE>': '10.131', '<VOL>': '45352'}, {'<TICKER>': 'HDR', '<DATE>': '19980327', '<CLOSE>': '10.027', '<VOL>': '42585'}, {'<TICKER>': 'HDR', '<DATE>': '19980330', '<CLOSE>': '10.027', '<VOL>': '21260'}]
</code></pre>
<p>修改代码</p>
<pre><code>for dictionary in dict_list:
for key in dictionary:
if key == "<DATE>" :
date = dictionary[key]
year = date[:4]
month = date[4:6]
day = date[6:]
date = f"{year}-{month}-{day}"
dictionary[key] = date
else:
pass
print(dict_list)
</code></pre>
<p><strong>您的预期产出</strong></p>
<pre><code>[{'<TICKER>': 'HDR', '<DATE>': '1998-03-17', '<CLOSE>': '11.633', '<VOL>': '67931'}, {'<TICKER>': 'HDR', '<DATE>': '1998-03-18', '<CLOSE>': '10.481', '<VOL>': '115169'}, {'<TICKER>': 'HDR', '<DATE>': '1998-03-19', '<CLOSE>': '10.131', '<VOL>': '75305'}, {'<TICKER>': 'HDR', '<DATE>': '1998-03-20', '<CLOSE>': '10.481', '<VOL>': '53504'}, {'<TICKER>': 'HDR', '<DATE>': '1998-03-23', '<CLOSE>': '10.379', '<VOL>': '27581'}, {'<TICKER>': 'HDR', '<DATE>': '1998-03-24', '<CLOSE>': '10.228', '<VOL>': '37328'}, {'<TICKER>': 'HDR', '<DATE>': '1998-03-25', '<CLOSE>': '10.131', '<VOL>': '28739'}, {'<TICKER>': 'HDR', '<DATE>': '1998-03-26', '<CLOSE>': '10.131', '<VOL>': '45352'}, {'<TICKER>': 'HDR', '<DATE>': '1998-03-27', '<CLOSE>': '10.027', '<VOL>': '42585'}, {'<TICKER>': 'HDR', '<DATE>': '1998-03-30', '<CLOSE>': '10.027', '<VOL>': '21260'}]
</code></pre>