[GitHub] [incubator-iceberg] TGooch44 commented on a change in pull request #551: [python] First add to docs, addresses #323 and #363
TGooch44 commented on a change in pull request #551: [python] First add to docs, addresses #323 and #363 URL: https://github.com/apache/incubator-iceberg/pull/551#discussion_r336134669 ## File path: site/docs/python-quickstart.md ## @@ -0,0 +1,40 @@ + + +# Examples + +## Inspect Table Metadata Review comment: added the following text: > Iceberg python is currently in development, and as such, should __only__ be used for development and testing purposes until an official release has been made. > > As such, we are not currently publishing to PyPi so the best way to install the library is to perform the following steps: Let me know if that sounds ok This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services - To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For additional commands, e-mail: issues-h...@iceberg.apache.org
[GitHub] [incubator-iceberg] TGooch44 commented on a change in pull request #551: [python] First add to docs, addresses #323 and #363
TGooch44 commented on a change in pull request #551: [python] First add to docs, addresses #323 and #363 URL: https://github.com/apache/incubator-iceberg/pull/551#discussion_r336131362 ## File path: python/README.md ## @@ -15,6 +15,26 @@ - limitations under the License. --> -# Iceberg -A python implementation of the Iceberg table format. -See the project level README for more details: https://github.com/apache/incubator-iceberg +# Iceberg Python + +Iceberg is a python library for programatic access to iceberg table metadata as well as data access. The intention is to provide a functional subset of the java library. + +## Getting Started + +We are not currently publishing to PyPi so the best way to install the library is to clone the git repo and do a pip install -e + +``` +git clone https://github.com/apache/incubator-iceberg.git +cd incubator-iceberg/python +pip install -e . Review comment: added tox instructions, let me know if that looks ok This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services - To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For additional commands, e-mail: issues-h...@iceberg.apache.org
[GitHub] [incubator-iceberg] TGooch44 commented on a change in pull request #551: [python] First add to docs, addresses #323 and #363
TGooch44 commented on a change in pull request #551: [python] First add to
docs, addresses #323 and #363
URL: https://github.com/apache/incubator-iceberg/pull/551#discussion_r336131555
##
File path: site/docs/python-api-intro.md
##
@@ -0,0 +1,143 @@
+
+
+# Iceberg Python API
+
+Much of the python api conforms to the java api. You can get more info about
the java api [here](https://iceberg.apache.org/api/).
+
+
+## Tables
+
+The Table interface provides access to table metadata
+
++ schema returns the current table schema
++ spec returns the current table partition spec
++ properties returns a map of key-value properties
++ currentSnapshot returns the current table snapshot
++ snapshots returns all valid snapshots for the table
++ snapshot(id) returns a specific snapshot by ID
++ location returns the table’s base location
+
+Tables also provide refresh to update the table to the latest version.
+
+### Scanning
+Iceberg table scans start by creating a TableScan object with newScan.
+
+``` python
+scan = table.new_scan();
+```
+
+To configure a scan, call filter and select on the TableScan to get a new
TableScan with those changes.
+
+``` python
+filtered_scan = scan.filter(Expressions.equal("id", 5))
+```
+
+String expressions can also be passed to the filter method.
+
+``` python
+filtered_scan = scan.filter("id=5")
+```
+
+Schema projections can be applied against a TableScan by passing a list of
column names.
+
+``` python
+filtered_scan = scan.select(["col_1", "col_2", "col_3"])
+```
+
+Because some data types cannot be read using the python library, a convenience
method for excluding columns from projection is provided.
+
+``` python
+filtered_scan = scan.select_except(["unsupported_col_1", "unsupported_col_2"])
+```
+
+
+Calls to configuration methods create a new TableScan so that each TableScan
is immutable.
+
+When a scan is configured, planFiles, planTasks, and schema are used to return
files, tasks, and the read projection.
+
+``` python
+scan = table.new_scan() \
+.filter("id=5") \
+.select(["id", "data"])
+
+projection = scan.schema
+for task in scan.plan_tasks():
+print(task)
+```
+
+## Types
+
+Iceberg data types are located in iceberg.api.types.types
+
+### Primitives
+
+Primitive type instances are available from static methods in each type class.
Types without parameters use get, and types like __decimal__ use factory
methods:
+
+```python
+IntegerType.get()# int
+DoubleType.get() # double
+DecimalType.of(9, 2) # decimal(9, 2)
+```
+
+### Nested types
+Structs, maps, and lists are created using factory methods in type classes.
+
+Like struct fields, map keys or values and list elements are tracked as nested
fields. Nested fields track [field
IDs](https://iceberg.apache.org/evolution/#correctness) and nullability.
+
+Struct fields are created using __NestedField.optional__ or
__NestedField.required__. Map value and list element nullability is set in the
map and list factory methods.
Review comment:
tried to match this up. let me know if it looks better.
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[GitHub] [incubator-iceberg] TGooch44 commented on a change in pull request #551: [python] First add to docs, addresses #323 and #363
TGooch44 commented on a change in pull request #551: [python] First add to
docs, addresses #323 and #363
URL: https://github.com/apache/incubator-iceberg/pull/551#discussion_r336131620
##
File path: site/docs/python-api-intro.md
##
@@ -0,0 +1,143 @@
+
+
+# Iceberg Python API
+
+Much of the python api conforms to the java api. You can get more info about
the java api [here](https://iceberg.apache.org/api/).
+
+
+## Tables
+
+The Table interface provides access to table metadata
+
++ schema returns the current table schema
++ spec returns the current table partition spec
++ properties returns a map of key-value properties
++ currentSnapshot returns the current table snapshot
++ snapshots returns all valid snapshots for the table
++ snapshot(id) returns a specific snapshot by ID
++ location returns the table’s base location
+
+Tables also provide refresh to update the table to the latest version.
+
+### Scanning
+Iceberg table scans start by creating a TableScan object with newScan.
+
+``` python
+scan = table.new_scan();
+```
+
+To configure a scan, call filter and select on the TableScan to get a new
TableScan with those changes.
+
+``` python
+filtered_scan = scan.filter(Expressions.equal("id", 5))
+```
+
+String expressions can also be passed to the filter method.
+
+``` python
+filtered_scan = scan.filter("id=5")
+```
+
+Schema projections can be applied against a TableScan by passing a list of
column names.
+
+``` python
+filtered_scan = scan.select(["col_1", "col_2", "col_3"])
+```
+
+Because some data types cannot be read using the python library, a convenience
method for excluding columns from projection is provided.
+
+``` python
+filtered_scan = scan.select_except(["unsupported_col_1", "unsupported_col_2"])
+```
+
+
+Calls to configuration methods create a new TableScan so that each TableScan
is immutable.
+
+When a scan is configured, planFiles, planTasks, and schema are used to return
files, tasks, and the read projection.
+
+``` python
+scan = table.new_scan() \
+.filter("id=5") \
+.select(["id", "data"])
+
+projection = scan.schema
+for task in scan.plan_tasks():
+print(task)
+```
+
+## Types
+
+Iceberg data types are located in iceberg.api.types.types
+
+### Primitives
+
+Primitive type instances are available from static methods in each type class.
Types without parameters use get, and types like __decimal__ use factory
methods:
+
+```python
+IntegerType.get()# int
+DoubleType.get() # double
+DecimalType.of(9, 2) # decimal(9, 2)
+```
+
+### Nested types
+Structs, maps, and lists are created using factory methods in type classes.
+
+Like struct fields, map keys or values and list elements are tracked as nested
fields. Nested fields track [field
IDs](https://iceberg.apache.org/evolution/#correctness) and nullability.
+
+Struct fields are created using __NestedField.optional__ or
__NestedField.required__. Map value and list element nullability is set in the
map and list factory methods.
+
+```python
+# struct<1 id: int, 2 data: optional string>
+struct = StructType.of([NestedField.required(1, "id", IntegerType.get()),
+NestedField.optional(2, "data", StringType.get()])
+ )
+```
+```python
+# map<1 key: int, 2 value: optional string>
+map_var = MapType.of_optional(1, IntegerType.get(),
+ 2, StringType.get())
+```
+```python
+# array<1 element: int>
+list_var = ListType.of_required(1, IntegerType.get());
+```
+
+## Expressions
+Iceberg’s expressions are used to configure table scans. To create
expressions, use the factory methods in Expressions.
+
+Supported predicate expressions are:
+
++ __is_null__
Review comment:
ditto for the above comment
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[GitHub] [incubator-iceberg] TGooch44 commented on a change in pull request #551: [python] First add to docs, addresses #323 and #363
TGooch44 commented on a change in pull request #551: [python] First add to docs, addresses #323 and #363 URL: https://github.com/apache/incubator-iceberg/pull/551#discussion_r336131188 ## File path: python/README.md ## @@ -15,6 +15,26 @@ - limitations under the License. --> -# Iceberg -A python implementation of the Iceberg table format. -See the project level README for more details: https://github.com/apache/incubator-iceberg +# Iceberg Python + +Iceberg is a python library for programatic access to iceberg table metadata as well as data access. The intention is to provide a functional subset of the java library. + +## Getting Started Review comment: added This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services - To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For additional commands, e-mail: issues-h...@iceberg.apache.org
