Invalid type for parameter error when using put_item dynamodb - amazon-dynamodb

Question

I want to write data in dataframe to dynamodb table
item = {}
for row in datasource_archived_df_join_repartition.rdd.collect():
item['x'] = row.x
item['y'] = row.y
client.put_item( TableName='tryfail',
Item=item)
but im gettin this error
Invalid type for parameter Item.x, value: 478.2, type: '<'type 'float''>', valid types: '<'type 'dict''>'
Invalid type for parameter Item.y, value: 696- 18C 12, type: '<'type 'unicode''>', valid types: '<'type 'dict''>'

Answer 1

Old question, but it still comes up high in a search and hasn't been answered properly, so here we go.
When putting an item in a DynamoDB table it must be a dictionary in a particular nested form that indicates to the database engine the data type of the value for each attribute. The form looks like below. The way to think of this is that an AttributeValue is not a bare variable value but a combination of that value and its type. For example, an AttributeValue for the AlbumTitle attribute below is the dict {'S': 'Somewhat Famous'} where the 'S' indicates a string type.
response = client.put_item(
TableName='Music',
Item={
'AlbumTitle': { # <-------------- Attribute
'S': 'Somewhat Famous', # <-- Attribute Value with type string ('S')
},
'Artist': {
'S': 'No One You Know',
},
'SongTitle': {
'S': 'Call Me Today',
},
'Year': {
'N': '2021' # <----------- Note that numeric values are supplied as strings
}
}
)
In your case (assuming x and y are numbers) you might want something like this:
for row in datasource_archived_df_join_repartition.rdd.collect():
item = {
'x': {'N': str(row.x)},
'y': {'N': str(row.y)}
}
client.put_item( TableName='tryfail', Item=item)
Two things to note here: first, each item corresponds to a row, so if you are putting items in a loop you must instantiate a new one with each iteration. Second, regarding the conversion of the numeric x and y into strings, the DynamoDB docs explain that the reason the AttributeValue dict requires this is "to maximize compatibility across languages and libraries. However, DynamoDB treats them as number type attributes for mathematical operations." For fuller documentation on the type system for DynamoDB take a look at this or read the Boto3 doc here since you are using Python.

Answer 2

The error message is indicating you are using the wrong type, it looks like you need to be using a dictionary when assigning values to item['x'] and item[y]. e.g.
item['x'] = {'value': row.x}
item['y'] = {'value': row.y}