Passing list of search string in contains in FilterExpression

Question

Is there any way to pass a list of search strings in the contains() method of FilterExpression in DynamoDb?

Something like below:

search_str = ['value-1', 'value-2', 'value-3']
result = kb_table.scan(
            FilterExpression="contains (title, :titleVal)", 
            ExpressionAttributeValues={ ":titleVal": search_str }
        )

For now I can only think of looping through the list and scanning the table multiple times (as in below code), but I think it will be resource heavy.

for item in search_str:
    result += kb_table.scan(
            FilterExpression="contains (title, :titleVal)", 
            ExpressionAttributeValues={ ":titleVal": item }
        )

Any suggestions.

Answer 1

对于上述场景，CONTAINS应与OR条件一起使用。当您将数组作为 的输入时CONTAINS，DynamoDB 将检查 SET 属性（“SS”、“NS”或“BS”）。它不会在字符串属性上查找子序列。

如果比较的目标属性是字符串类型，则运算符检查子字符串匹配。如果比较的目标属性是 Binary 类型，则运算符会查找与输入匹配的目标的子序列。如果比较的目标属性是一个集合（“SS”、“NS”或“BS”），那么如果找到与集合的任何成员完全匹配的运算符，则计算结果为真。

例子：-

movies1 = "MyMovie"
movies2 = "Big New"
fe1 = Attr('title').contains(movies1)
fe2 = Attr('title').contains(movies2)

response = table.scan(
        FilterExpression=fe1 or fe2        
    )