下面是我的代码，我正在使用：
with open(r'C:\Users\Manish\Desktop\File5.txt', 'r') as f:
fo = f.read(20)
print(fo)
f.seek(20,1)
fo = f.read(20)
print(fo)
但它没有从当前位置获取下一行，而是反复向我显示错误。我的代码问题出在哪里？
我有下表，我想要其 userid='user-1' 和 gridname='RT' 的布局名称
| userid | defaultdata |
|--------|------------------------------------------------------------------------------------------|
| user-1 | [{"gridname":"RT", "layoutname":"layout-1"},{"gridname":"RT2", "layoutname":"layout-2"}] |
| user-2 | [{"gridname":"RT", "layoutname":"layout-3"},{"gridname":"RT2", "layoutname":"layout-2"}] |
到目前为止，我已经尝试过这个。
SELECT userid, obj.value->>'gridname' AS gridname
FROM col.userdefault t
JOIN lateral jsonb_array_elements(t.defaultdata::jsonb) obj(value) ON
obj.value->>'_gridname' = 'RT'
WHERE defaultdata @> '[{"_gridname":"RT"}]';
但不工作并收到以下错误：
ERROR: operator does not exist: json @> unknown
LINE 4: WHERE defaultdata @> '[{"_gridname":"RT"}]::jsonb';
^
HINT: No operator matches the given name and argument types. You might need to add explicit type casts. …我有两个变量，一个是字符串，另一个是列表。
string_val = 'CreateTime:1557770979668 {"schema":{"type":"string","optional":false},"payload":"{\"subscriptionId\":\"//blp/mktdata/BLOOMBERG IDENTIFIER?fields=LAST_PRICE\",\"MarketDataEvents\":{\"LAST_PRICE\":50.84}}"}'
list_val = ["25746UCY3 Corp","BBG00JM9XLN6 Equity","CFM0987JKM Pro"]
在所需的输出中，您可以观察到插入了list_val元素而不是“ BLOOMBERG IDENTIFIER”。我尝试了下面的代码，但没有成功。
for i in range(0,len(list_val)):
print(len(list_val))
expect_val = string_val.split('mktdata/',0)[1] + list_val[i] + string_val.split('?fields',0)[-1]
print(expect_val)
所需的输出：
CreateTime:1557770979668 {"schema":{"type":"string","optional":false},"payload":"{\"subscriptionId\":\"//blp/mktdata/25746UCY3 Corp?fields=LAST_PRICE\",\"MarketDataEvents\":{\"LAST_PRICE\":50.84}}"}
CreateTime:1557770979668 {"schema":{"type":"string","optional":false},"payload":"{\"subscriptionId\":\"//blp/mktdata/BBG00JM9XLN6 Equity?fields=LAST_PRICE\",\"MarketDataEvents\":{\"LAST_PRICE\":50.84}}"}
CreateTime:1557770979668 {"schema":{"type":"string","optional":false},"payload":"{\"subscriptionId\":\"//blp/mktdata/CFM0987JKM Pro?fields=LAST_PRICE\",\"MarketDataEvents\":{\"LAST_PRICE\":50.84}}"}
请提出建议，我该如何实现？