Python列表用[:]取字段报索引类型错误 批量计算日期差怎么解决

错误原因 #

你触发报错的核心原因是：data['activities'][:]返回的是activities列表本身，Python原生列表不支持直接用字符串作为键，批量提取所有子元素的对应字段，所以才会抛出'list indices must be integers or slices, not str'的类型错误。

修复方案 #

不需要重写原有逻辑，仅需对activities列表加一层遍历即可，你原有的秒级时间差计算逻辑可以完全复用，修改后的完整代码如下：

import json
import datetime
import copy

# 读取json文件
with open('/Users/kenyacastellanos/Downloads/data.json') as json_data_file:
    data = json.load(json_data_file)
print(data)

# 打印前10条未排序数据
print("Sin ordenar:",data['activities'][:10])

## 按user_id字段排序
data['activities'].sort(key = lambda x: x['user_id'])

# 打印前10条排序后数据
print("Ordenamos:", data['activities'][:10])

# 批量计算所有条目的时间差
for activity in data['activities']:
    date1 = datetime.datetime.fromisoformat(activity['answered_at'])
    date2 = datetime.datetime.fromisoformat(activity['first_seen_at'])
    difference_date = (date1-date2)
    print(f"ID: {activity['id']}  Duration in seconds: {difference_date.seconds} {difference_date.microseconds}")

如果需要单独提取所有条目的answered_at或first_seen_at字段，也可以用列表推导式实现：

# 提取所有answered_at字段
all_answered_at = [item['answered_at'] for item in data['activities']]
# 提取所有first_seen_at字段
all_first_seen = [item['first_seen_at'] for item in data['activities']]

内容的提问来源于stack exchange，提问作者Kenncd