Passing list of search string in contains in FilterExpression - amazon-dynamodb

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

For the above scenario, the CONTAINS should be used with OR condition. When you give array as input for CONTAINS, DynamoDB will check for the SET attribute ("SS", "NS", or "BS"). It doesn't looks for the sub-sequence on the string attribute.
If the target attribute of the comparison is of type String, then the
operator checks for a substring match. If the target attribute of the
comparison is of type Binary, then the operator looks for a
subsequence of the target that matches the input. If the target
attribute of the comparison is a set ("SS", "NS", or "BS"), then the
operator evaluates to true if it finds an exact match with any member
of the set.
Example:-
movies1 = "MyMovie"
movies2 = "Big New"
fe1 = Attr('title').contains(movies1)
fe2 = Attr('title').contains(movies2)
response = table.scan(
FilterExpression=fe1 or fe2
)

Answer 2

a little bit late but to allow people to find a solution i give here my method.
lets assume that in your DB you have a props called 'EMAIL you want to filter your scan on this EMAIL with a list of value. you can proceed as following.
list_of_elem=['mail1#mail.com','mail2#mail.com','mail3#mail.com']
#set an empty string to create your query
stringquery=""
# loop each element in your list
for index,value in enumerate(list_of_elem):
# add your query of contains with mail value
stringquery=stringquery+f"Attr('EMAIL').contains('{value }')"
# while your value is not the last element in list add the 'OR' operator
if index < len(list_of_elem)-1:
stringquery=stringquery+ ' | '
dynamodb = boto3.resource('dynamodb')
# Use eval of your query string to parse the string as filter expression
tableUser = dynamodb.Table('mytable')
tableUser.scan(
FilterExpression=eval(stringquery)
)