DynamoDB.Paginator.
Scan
¶paginator = client.get_paginator('scan')
paginate
(**kwargs)¶Creates an iterator that will paginate through responses from DynamoDB.Client.scan()
.
See also: AWS API Documentation
Request Syntax
response_iterator = paginator.paginate(
TableName='string',
IndexName='string',
AttributesToGet=[
'string',
],
Select='ALL_ATTRIBUTES'|'ALL_PROJECTED_ATTRIBUTES'|'SPECIFIC_ATTRIBUTES'|'COUNT',
ScanFilter={
'string': {
'AttributeValueList': [
{
'S': 'string',
'N': 'string',
'B': b'bytes',
'SS': [
'string',
],
'NS': [
'string',
],
'BS': [
b'bytes',
],
'M': {
'string': {'... recursive ...'}
},
'L': [
{'... recursive ...'},
],
'NULL': True|False,
'BOOL': True|False
},
],
'ComparisonOperator': 'EQ'|'NE'|'IN'|'LE'|'LT'|'GE'|'GT'|'BETWEEN'|'NOT_NULL'|'NULL'|'CONTAINS'|'NOT_CONTAINS'|'BEGINS_WITH'
}
},
ConditionalOperator='AND'|'OR',
ReturnConsumedCapacity='INDEXES'|'TOTAL'|'NONE',
TotalSegments=123,
Segment=123,
ProjectionExpression='string',
FilterExpression='string',
ExpressionAttributeNames={
'string': 'string'
},
ExpressionAttributeValues={
'string': {
'S': 'string',
'N': 'string',
'B': b'bytes',
'SS': [
'string',
],
'NS': [
'string',
],
'BS': [
b'bytes',
],
'M': {
'string': {'... recursive ...'}
},
'L': [
{'... recursive ...'},
],
'NULL': True|False,
'BOOL': True|False
}
},
ConsistentRead=True|False,
PaginationConfig={
'MaxItems': 123,
'PageSize': 123,
'StartingToken': 'string'
}
)
[REQUIRED]
The name of the table containing the requested items; or, if you provide IndexName
, the name of the table to which that index belongs.
IndexName
parameter, you must also provide TableName
.This is a legacy parameter. Use ProjectionExpression
instead. For more information, see AttributesToGet in the Amazon DynamoDB Developer Guide .
The attributes to be returned in the result. You can retrieve all item attributes, specific item attributes, the count of matching items, or in the case of an index, some or all of the attributes projected into the index.
ALL_ATTRIBUTES
- Returns all of the item attributes from the specified table or index. If you query a local secondary index, then for each matching item in the index, DynamoDB fetches the entire item from the parent table. If the index is configured to project all item attributes, then all of the data can be obtained from the local secondary index, and no fetching is required.ALL_PROJECTED_ATTRIBUTES
- Allowed only when querying an index. Retrieves all attributes that have been projected into the index. If the index is configured to project all attributes, this return value is equivalent to specifying ALL_ATTRIBUTES
.COUNT
- Returns the number of matching items, rather than the matching items themselves. Note that this uses the same quantity of read capacity units as getting the items, and is subject to the same item size calculations.SPECIFIC_ATTRIBUTES
- Returns only the attributes listed in ProjectionExpression
. This return value is equivalent to specifying ProjectionExpression
without specifying any value for Select
. If you query or scan a local secondary index and request only attributes that are projected into that index, the operation reads only the index and not the table. If any of the requested attributes are not projected into the local secondary index, DynamoDB fetches each of these attributes from the parent table. This extra fetching incurs additional throughput cost and latency. If you query or scan a global secondary index, you can only request attributes that are projected into the index. Global secondary index queries cannot fetch attributes from the parent table.If neither Select
nor ProjectionExpression
are specified, DynamoDB defaults to ALL_ATTRIBUTES
when accessing a table, and ALL_PROJECTED_ATTRIBUTES
when accessing an index. You cannot use both Select
and ProjectionExpression
together in a single request, unless the value for Select
is SPECIFIC_ATTRIBUTES
. (This usage is equivalent to specifying ProjectionExpression
without any value for Select
.)
Note
If you use the ProjectionExpression
parameter, then the value for Select
can only be SPECIFIC_ATTRIBUTES
. Any other value for Select
will return an error.
This is a legacy parameter. Use FilterExpression
instead. For more information, see ScanFilter in the Amazon DynamoDB Developer Guide .
Represents the selection criteria for a Query
or Scan
operation:
Query
operation, Condition
is used for specifying the KeyConditions
to use when querying a table or an index. For KeyConditions
, only the following comparison operators are supported: EQ | LE | LT | GE | GT | BEGINS_WITH | BETWEEN
Condition
is also used in a QueryFilter
, which evaluates the query results and returns only the desired values.Scan
operation, Condition
is used in a ScanFilter
, which evaluates the scan results and returns only the desired values.One or more values to evaluate against the supplied attribute. The number of values in the list depends on the ComparisonOperator
being used.
For type Number, value comparisons are numeric.
String value comparisons for greater than, equals, or less than are based on ASCII character code values. For example, a
is greater than A
, and a
is greater than B
. For a list of code values, see http://en.wikipedia.org/wiki/ASCII#ASCII_printable_characters.
For Binary, DynamoDB treats each byte of the binary data as unsigned when it compares binary values.
Represents the data for an attribute.
Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.
For more information, see Data Types in the Amazon DynamoDB Developer Guide .
An attribute of type String. For example:
"S": "Hello"
An attribute of type Number. For example:
"N": "123.45"
Numbers are sent across the network to DynamoDB as strings, to maximize compatibility across languages and libraries. However, DynamoDB treats them as number type attributes for mathematical operations.
An attribute of type Binary. For example:
"B": "dGhpcyB0ZXh0IGlzIGJhc2U2NC1lbmNvZGVk"
An attribute of type String Set. For example:
"SS": ["Giraffe", "Hippo" ,"Zebra"]
An attribute of type Number Set. For example:
"NS": ["42.2", "-19", "7.5", "3.14"]
Numbers are sent across the network to DynamoDB as strings, to maximize compatibility across languages and libraries. However, DynamoDB treats them as number type attributes for mathematical operations.
An attribute of type Binary Set. For example:
"BS": ["U3Vubnk=", "UmFpbnk=", "U25vd3k="]
An attribute of type Map. For example:
"M": {"Name": {"S": "Joe"}, "Age": {"N": "35"}}
Represents the data for an attribute.
Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.
For more information, see Data Types in the Amazon DynamoDB Developer Guide .
An attribute of type List. For example:
"L": [ {"S": "Cookies"} , {"S": "Coffee"}, {"N": "3.14159"}]
Represents the data for an attribute.
Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.
For more information, see Data Types in the Amazon DynamoDB Developer Guide .
An attribute of type Null. For example:
"NULL": true
An attribute of type Boolean. For example:
"BOOL": true
A comparator for evaluating attributes. For example, equals, greater than, less than, etc.
The following comparison operators are available:
EQ | NE | LE | LT | GE | GT | NOT_NULL | NULL | CONTAINS | NOT_CONTAINS | BEGINS_WITH | IN | BETWEEN
The following are descriptions of each comparison operator.
EQ
: Equal. EQ
is supported for all data types, including lists and maps. AttributeValueList
can contain only one AttributeValue
element of type String, Number, Binary, String Set, Number Set, or Binary Set. If an item contains an AttributeValue
element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"}
does not equal {"N":"6"}
. Also, {"N":"6"}
does not equal {"NS":["6", "2", "1"]}
.NE
: Not equal. NE
is supported for all data types, including lists and maps. AttributeValueList
can contain only one AttributeValue
of type String, Number, Binary, String Set, Number Set, or Binary Set. If an item contains an AttributeValue
of a different type than the one provided in the request, the value does not match. For example, {"S":"6"}
does not equal {"N":"6"}
. Also, {"N":"6"}
does not equal {"NS":["6", "2", "1"]}
.LE
: Less than or equal. AttributeValueList
can contain only one AttributeValue
element of type String, Number, or Binary (not a set type). If an item contains an AttributeValue
element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"}
does not equal {"N":"6"}
. Also, {"N":"6"}
does not compare to {"NS":["6", "2", "1"]}
.LT
: Less than. AttributeValueList
can contain only one AttributeValue
of type String, Number, or Binary (not a set type). If an item contains an AttributeValue
element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"}
does not equal {"N":"6"}
. Also, {"N":"6"}
does not compare to {"NS":["6", "2", "1"]}
.GE
: Greater than or equal. AttributeValueList
can contain only one AttributeValue
element of type String, Number, or Binary (not a set type). If an item contains an AttributeValue
element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"}
does not equal {"N":"6"}
. Also, {"N":"6"}
does not compare to {"NS":["6", "2", "1"]}
.GT
: Greater than. AttributeValueList
can contain only one AttributeValue
element of type String, Number, or Binary (not a set type). If an item contains an AttributeValue
element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"}
does not equal {"N":"6"}
. Also, {"N":"6"}
does not compare to {"NS":["6", "2", "1"]}
.NOT_NULL
: The attribute exists. NOT_NULL
is supported for all data types, including lists and maps.Note
This operator tests for the existence of an attribute, not its data type. If the data type of attribute " a
" is null, and you evaluate it using NOT_NULL
, the result is a Boolean true
. This result is because the attribute " a
" exists; its data type is not relevant to the NOT_NULL
comparison operator.
NULL
: The attribute does not exist. NULL
is supported for all data types, including lists and maps.Note
This operator tests for the nonexistence of an attribute, not its data type. If the data type of attribute " a
" is null, and you evaluate it using NULL
, the result is a Boolean false
. This is because the attribute " a
" exists; its data type is not relevant to the NULL
comparison operator.
CONTAINS
: Checks for a subsequence, or value in a set. AttributeValueList
can contain only one AttributeValue
element of type String, Number, or Binary (not a set type). 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. CONTAINS is supported for lists: When evaluating " a CONTAINS b
", " a
" can be a list; however, " b
" cannot be a set, a map, or a list.NOT_CONTAINS
: Checks for absence of a subsequence, or absence of a value in a set. AttributeValueList
can contain only one AttributeValue
element of type String, Number, or Binary (not a set type). If the target attribute of the comparison is a String, then the operator checks for the absence of a substring match. If the target attribute of the comparison is Binary, then the operator checks for the absence of 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 does not find an exact match with any member of the set. NOT_CONTAINS is supported for lists: When evaluating " a NOT CONTAINS b
", " a
" can be a list; however, " b
" cannot be a set, a map, or a list.BEGINS_WITH
: Checks for a prefix. AttributeValueList
can contain only one AttributeValue
of type String or Binary (not a Number or a set type). The target attribute of the comparison must be of type String or Binary (not a Number or a set type).IN
: Checks for matching elements in a list. AttributeValueList
can contain one or more AttributeValue
elements of type String, Number, or Binary. These attributes are compared against an existing attribute of an item. If any elements of the input are equal to the item attribute, the expression evaluates to true.BETWEEN
: Greater than or equal to the first value, and less than or equal to the second value. AttributeValueList
must contain two AttributeValue
elements of the same type, either String, Number, or Binary (not a set type). A target attribute matches if the target value is greater than, or equal to, the first element and less than, or equal to, the second element. If an item contains an AttributeValue
element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"}
does not compare to {"N":"6"}
. Also, {"N":"6"}
does not compare to {"NS":["6", "2", "1"]}
For usage examples of AttributeValueList
and ComparisonOperator
, see Legacy Conditional Parameters in the Amazon DynamoDB Developer Guide .
FilterExpression
instead. For more information, see ConditionalOperator in the Amazon DynamoDB Developer Guide .Determines the level of detail about either provisioned or on-demand throughput consumption that is returned in the response:
INDEXES
- The response includes the aggregate ConsumedCapacity
for the operation, together with ConsumedCapacity
for each table and secondary index that was accessed. Note that some operations, such as GetItem
and BatchGetItem
, do not access any indexes at all. In these cases, specifying INDEXES
will only return ConsumedCapacity
information for table(s).TOTAL
- The response includes only the aggregate ConsumedCapacity
for the operation.NONE
- No ConsumedCapacity
details are included in the response.For a parallel Scan
request, TotalSegments
represents the total number of segments into which the Scan
operation will be divided. The value of TotalSegments
corresponds to the number of application workers that will perform the parallel scan. For example, if you want to use four application threads to scan a table or an index, specify a TotalSegments
value of 4.
The value for TotalSegments
must be greater than or equal to 1, and less than or equal to 1000000. If you specify a TotalSegments
value of 1, the Scan
operation will be sequential rather than parallel.
If you specify TotalSegments
, you must also specify Segment
.
For a parallel Scan
request, Segment
identifies an individual segment to be scanned by an application worker.
Segment IDs are zero-based, so the first segment is always 0. For example, if you want to use four application threads to scan a table or an index, then the first thread specifies a Segment
value of 0, the second thread specifies 1, and so on.
The value of LastEvaluatedKey
returned from a parallel Scan
request must be used as ExclusiveStartKey
with the same segment ID in a subsequent Scan
operation.
The value for Segment
must be greater than or equal to 0, and less than the value provided for TotalSegments
.
If you provide Segment
, you must also provide TotalSegments
.
A string that identifies one or more attributes to retrieve from the specified table or index. These attributes can include scalars, sets, or elements of a JSON document. The attributes in the expression must be separated by commas.
If no attribute names are specified, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
For more information, see Specifying Item Attributes in the Amazon DynamoDB Developer Guide .
A string that contains conditions that DynamoDB applies after the Scan
operation, but before the data is returned to you. Items that do not satisfy the FilterExpression
criteria are not returned.
Note
A FilterExpression
is applied after the items have already been read; the process of filtering does not consume any additional read capacity units.
For more information, see Filter Expressions in the Amazon DynamoDB Developer Guide .
One or more substitution tokens for attribute names in an expression. The following are some use cases for using ExpressionAttributeNames
:
Use the # character in an expression to dereference an attribute name. For example, consider the following attribute name:
Percentile
The name of this attribute conflicts with a reserved word, so it cannot be used directly in an expression. (For the complete list of reserved words, see Reserved Words in the Amazon DynamoDB Developer Guide ). To work around this, you could specify the following for ExpressionAttributeNames
:
{"#P":"Percentile"}
You could then use this substitution in an expression, as in this example:
#P = :val
Note
Tokens that begin with the : character are expression attribute values , which are placeholders for the actual value at runtime.
For more information on expression attribute names, see Specifying Item Attributes in the Amazon DynamoDB Developer Guide .
One or more values that can be substituted in an expression.
Use the : (colon) character in an expression to dereference an attribute value. For example, suppose that you wanted to check whether the value of the ProductStatus
attribute was one of the following:
Available | Backordered | Discontinued
You would first need to specify ExpressionAttributeValues
as follows:
{ ":avail":{"S":"Available"}, ":back":{"S":"Backordered"}, ":disc":{"S":"Discontinued"} }
You could then use these values in an expression, such as this:
ProductStatus IN (:avail, :back, :disc)
For more information on expression attribute values, see Condition Expressions in the Amazon DynamoDB Developer Guide .
Represents the data for an attribute.
Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.
For more information, see Data Types in the Amazon DynamoDB Developer Guide .
An attribute of type String. For example:
"S": "Hello"
An attribute of type Number. For example:
"N": "123.45"
Numbers are sent across the network to DynamoDB as strings, to maximize compatibility across languages and libraries. However, DynamoDB treats them as number type attributes for mathematical operations.
An attribute of type Binary. For example:
"B": "dGhpcyB0ZXh0IGlzIGJhc2U2NC1lbmNvZGVk"
An attribute of type String Set. For example:
"SS": ["Giraffe", "Hippo" ,"Zebra"]
An attribute of type Number Set. For example:
"NS": ["42.2", "-19", "7.5", "3.14"]
Numbers are sent across the network to DynamoDB as strings, to maximize compatibility across languages and libraries. However, DynamoDB treats them as number type attributes for mathematical operations.
An attribute of type Binary Set. For example:
"BS": ["U3Vubnk=", "UmFpbnk=", "U25vd3k="]
An attribute of type Map. For example:
"M": {"Name": {"S": "Joe"}, "Age": {"N": "35"}}
Represents the data for an attribute.
Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.
For more information, see Data Types in the Amazon DynamoDB Developer Guide .
An attribute of type List. For example:
"L": [ {"S": "Cookies"} , {"S": "Coffee"}, {"N": "3.14159"}]
Represents the data for an attribute.
Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.
For more information, see Data Types in the Amazon DynamoDB Developer Guide .
An attribute of type Null. For example:
"NULL": true
An attribute of type Boolean. For example:
"BOOL": true
A Boolean value that determines the read consistency model during the scan:
ConsistentRead
is false
, then the data returned from Scan
might not contain the results from other recently completed write operations ( PutItem
, UpdateItem
, or DeleteItem
).ConsistentRead
is true
, then all of the write operations that completed before the Scan
began are guaranteed to be contained in the Scan
response.The default setting for ConsistentRead
is false
.
The ConsistentRead
parameter is not supported on global secondary indexes. If you scan a global secondary index with ConsistentRead
set to true, you will receive a ValidationException
.
A dictionary that provides parameters to control pagination.
The total number of items to return. If the total number of items available is more than the value specified in max-items then a NextToken
will be provided in the output that you can use to resume pagination.
The size of each page.
A token to specify where to start paginating. This is the NextToken
from a previous response.
dict
Response Syntax
{
'Items': [
{
'string': {
'S': 'string',
'N': 'string',
'B': b'bytes',
'SS': [
'string',
],
'NS': [
'string',
],
'BS': [
b'bytes',
],
'M': {
'string': {'... recursive ...'}
},
'L': [
{'... recursive ...'},
],
'NULL': True|False,
'BOOL': True|False
}
},
],
'Count': 123,
'ScannedCount': 123,
'ConsumedCapacity': {
'TableName': 'string',
'CapacityUnits': 123.0,
'ReadCapacityUnits': 123.0,
'WriteCapacityUnits': 123.0,
'Table': {
'ReadCapacityUnits': 123.0,
'WriteCapacityUnits': 123.0,
'CapacityUnits': 123.0
},
'LocalSecondaryIndexes': {
'string': {
'ReadCapacityUnits': 123.0,
'WriteCapacityUnits': 123.0,
'CapacityUnits': 123.0
}
},
'GlobalSecondaryIndexes': {
'string': {
'ReadCapacityUnits': 123.0,
'WriteCapacityUnits': 123.0,
'CapacityUnits': 123.0
}
}
},
'NextToken': 'string'
}
Response Structure
(dict) --
Represents the output of a Scan
operation.
Items (list) --
An array of item attributes that match the scan criteria. Each element in this array consists of an attribute name and the value for that attribute.
(dict) --
(string) --
(dict) --
Represents the data for an attribute.
Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.
For more information, see Data Types in the Amazon DynamoDB Developer Guide .
S (string) --
An attribute of type String. For example:
"S": "Hello"
N (string) --
An attribute of type Number. For example:
"N": "123.45"
Numbers are sent across the network to DynamoDB as strings, to maximize compatibility across languages and libraries. However, DynamoDB treats them as number type attributes for mathematical operations.
B (bytes) --
An attribute of type Binary. For example:
"B": "dGhpcyB0ZXh0IGlzIGJhc2U2NC1lbmNvZGVk"
SS (list) --
An attribute of type String Set. For example:
"SS": ["Giraffe", "Hippo" ,"Zebra"]
NS (list) --
An attribute of type Number Set. For example:
"NS": ["42.2", "-19", "7.5", "3.14"]
Numbers are sent across the network to DynamoDB as strings, to maximize compatibility across languages and libraries. However, DynamoDB treats them as number type attributes for mathematical operations.
BS (list) --
An attribute of type Binary Set. For example:
"BS": ["U3Vubnk=", "UmFpbnk=", "U25vd3k="]
M (dict) --
An attribute of type Map. For example:
"M": {"Name": {"S": "Joe"}, "Age": {"N": "35"}}
(string) --
(dict) --
Represents the data for an attribute.
Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.
For more information, see Data Types in the Amazon DynamoDB Developer Guide .
L (list) --
An attribute of type List. For example:
"L": [ {"S": "Cookies"} , {"S": "Coffee"}, {"N": "3.14159"}]
(dict) --
Represents the data for an attribute.
Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.
For more information, see Data Types in the Amazon DynamoDB Developer Guide .
NULL (boolean) --
An attribute of type Null. For example:
"NULL": true
BOOL (boolean) --
An attribute of type Boolean. For example:
"BOOL": true
Count (integer) --
The number of items in the response.
If you set ScanFilter
in the request, then Count
is the number of items returned after the filter was applied, and ScannedCount
is the number of matching items before the filter was applied.
If you did not use a filter in the request, then Count
is the same as ScannedCount
.
ScannedCount (integer) --
The number of items evaluated, before any ScanFilter
is applied. A high ScannedCount
value with few, or no, Count
results indicates an inefficient Scan
operation. For more information, see Count and ScannedCount in the Amazon DynamoDB Developer Guide .
If you did not use a filter in the request, then ScannedCount
is the same as Count
.
ConsumedCapacity (dict) --
The capacity units consumed by the Scan
operation. The data returned includes the total provisioned throughput consumed, along with statistics for the table and any indexes involved in the operation. ConsumedCapacity
is only returned if the ReturnConsumedCapacity
parameter was specified. For more information, see Provisioned Throughput in the Amazon DynamoDB Developer Guide .
TableName (string) --
The name of the table that was affected by the operation.
CapacityUnits (float) --
The total number of capacity units consumed by the operation.
ReadCapacityUnits (float) --
The total number of read capacity units consumed by the operation.
WriteCapacityUnits (float) --
The total number of write capacity units consumed by the operation.
Table (dict) --
The amount of throughput consumed on the table affected by the operation.
ReadCapacityUnits (float) --
The total number of read capacity units consumed on a table or an index.
WriteCapacityUnits (float) --
The total number of write capacity units consumed on a table or an index.
CapacityUnits (float) --
The total number of capacity units consumed on a table or an index.
LocalSecondaryIndexes (dict) --
The amount of throughput consumed on each local index affected by the operation.
(string) --
(dict) --
Represents the amount of provisioned throughput capacity consumed on a table or an index.
ReadCapacityUnits (float) --
The total number of read capacity units consumed on a table or an index.
WriteCapacityUnits (float) --
The total number of write capacity units consumed on a table or an index.
CapacityUnits (float) --
The total number of capacity units consumed on a table or an index.
GlobalSecondaryIndexes (dict) --
The amount of throughput consumed on each global index affected by the operation.
(string) --
(dict) --
Represents the amount of provisioned throughput capacity consumed on a table or an index.
ReadCapacityUnits (float) --
The total number of read capacity units consumed on a table or an index.
WriteCapacityUnits (float) --
The total number of write capacity units consumed on a table or an index.
CapacityUnits (float) --
The total number of capacity units consumed on a table or an index.
NextToken (string) --
A token to resume pagination.