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Python-typing-koans

A set of examples to learn optional static typing in Python.

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Idea

One of the best ways to learn python-typing is to annotate the code. In this repo, koans directory contains a set of files which will teach you python type-hints by fixing errors. The files carry a suffix from 100 in the increasing order. By solving errors in the each file in the increasing suffix order, you will gain knowledge about Python hints. It starts with simple variable annotation and covers topics function annotation, generics, protocols, classes.

How to learn?

The existing files has no annotations or wrong annotation, as a learner, you run one file and fix each errors till there are no type-errors. In the next section, you will learn, how to list all koans and how to run the modified koan file.

All the koan files are present in the following directories

koans/py
koans/dj_koans/mysite/polls/koans

How to run?

$cat koans/py/100-easy-variable-wrong-type.py
# msg variable is wrongly annotated as int, annotate it as string
msg: int = "hello world!"

# salary is annotated as int, annotate as float
salary: int = 2345.67

# Set is_active as bool
is_active: int = True
$poetry run python cli.py one koans/py/100-easy-variable-wrong-type.py
─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
Running Mypy on koan file koans/py/100-easy-variable-wrong-type.py
──────────────────────────────────  Mypy errors in koan file koans/py/100-easy-variable-wrong-type.py ───────────────────────────────────
koans/py/100-easy-variable-wrong-type.py:2: error: Incompatible types in assignment (expression has type "str", variable has type "int")
    msg: int = "hello world!"
               ^
koans/py/100-easy-variable-wrong-type.py:5: error: Incompatible types in assignment (expression has type "float", variable has type
"int")
    salary: int = 2345.67
                  ^
Found 2 errors in 1 file (checked 1 source file)

────────────────────────────────────────────────────────────────── End ──────────────────────────────────────────────────────────────────
─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
$poetry run python cli.py one koans/py/100-easy-variable-wrong-type.py
─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
Running Mypy on koan file koans/py/100-easy-variable-wrong-type.py
No errors in koan file koans/py/100-easy-variable-wrong-type.py 👍
─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
$poetry run python cli.py list
─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
koans/py/100-easy-variable-wrong-type.py
koans/py/101-easy-tuple-value.py
koans/py/102-easy-list-homogenous.py
koans/py/103-easy-mixed-values.py
koans/py/104-easy-union-example.py
koans/py/105-easy-dictionary-example.py
koans/py/106-easy-function-example.py
koans/py/107-easy-typed-dict.py
koans/py/108-easy-type-alias.py
koans/py/109-easy-user-defined-class.py
koans/py/110-easy-class-variable.py
koans/py/111-medium-callable-annotate.py
koans/py/112-medium-type-as-example.py
koans/py/113-easy-builder-pattern.py
koans/py/114-medium-factory-pattern.py
koans/py/115-medium-protocol-covariant-dbapi-example.py
koans/py/116-easy-factory-example.py
koans/py/117-easy-protocol-across-objects.py
koans/py/118-medium-protocol-behave-like-dict.py
koans/py/119-medium-queue-genrics.py
koans/py/120-medium-decorator.py
─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
$poetry run python cli.py summary
─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
 Ran mypy in koan file: koans/py/100-easy-variable-wrong-type.py 👍
 Ran mypy in koan file: koans/py/101-easy-tuple-value.py 👎
 Ran mypy in koan file: koans/py/102-easy-list-homogenous.py 👎
 Ran mypy in koan file: koans/py/103-easy-mixed-values.py 👎
 Ran mypy in koan file: koans/py/104-easy-union-example.py 👎
 Ran mypy in koan file: koans/py/105-easy-dictionary-example.py 👎
 Ran mypy in koan file: koans/py/106-easy-function-example.py 👎
 Ran mypy in koan file: koans/py/107-easy-typed-dict.py 👎
 Ran mypy in koan file: koans/py/108-easy-type-alias.py 👎
 Ran mypy in koan file: koans/py/109-easy-user-defined-class.py 👎
 Ran mypy in koan file: koans/py/110-easy-class-variable.py 👎
 Ran mypy in koan file: koans/py/111-medium-callable-annotate.py 👎
 Ran mypy in koan file: koans/py/112-medium-type-as-example.py 👎
 Ran mypy in koan file: koans/py/113-easy-builder-pattern.py 👎
 Ran mypy in koan file: koans/py/114-medium-factory-pattern.py 👎
 Ran mypy in koan file: koans/py/115-medium-protocol-covariant-dbapi-example.py 👎
 Ran mypy in koan file: koans/py/116-easy-factory-example.py 👎
 Ran mypy in koan file: koans/py/117-easy-protocol-across-objects.py 👎
 Ran mypy in koan file: koans/py/118-medium-protocol-behave-like-dict.py 👎
 Ran mypy in koan file: koans/py/119-medium-queue-genrics.py 👎
 Ran mypy in koan file: koans/py/120-medium-decorator.py 👎
  Koans Summary
┏━━━━━━━━┳━━━━━━━┓
┃ Status ┃ Count ┃
┡━━━━━━━━╇━━━━━━━┩
│ Passed │ 1     │
│ Failed │ 20    │
└────────┴───────┘
─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────

Resource for learning Python type-hints

Supported Koans

How to contribute?

To Support