Python - podsumowanie

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# Python

### Podsumowanie 2/2

### 07/06/2019

Paweł Suder

<pasuder@agh.edu.pl>

https://pasuder.github.io/labs/doc/lab06

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# Agenda

1. Tematy
2. Materiały

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# Tematy

Na dzisiaj:

- python
- dodatkowe materiały

---

## python

- typy podstawowe: set i dict
- instrukcje sterujące
- funkcje: parametry, domknięcia i dekoratory
- interpreter

---

## python - typy

Typy wbudowane - wybrane przykłady:

- [zbiory](https://docs.python.org/3/library/stdtypes.html#set-types-set-frozenset)
- [słowniki](https://docs.python.org/3/library/stdtypes.html#mapping-types-dict)

---

## python - typy

```python
>>> i = {0, 1, 2}
>>> type(i)
<class 'set'>

>>> i = {0:'0', 1:'1', 2:'2'}
>>> type(i)
<class 'dict'>
```

---

## python

Instrukcje [sterujące](https://docs.python.org/3/tutorial/controlflow.html):

- warunkowe [`if`](https://docs.python.org/3/tutorial/controlflow.html#if-statements)
- pętle [`while`](https://docs.python.org/3/tutorial/introduction.html#first-steps-towards-programming) i [`for`](https://docs.python.org/3/tutorial/controlflow.html#for-statements)
  - sterowanie w pętli przy pomocy [`break`, `continue` i `else`](https://docs.python.org/3/tutorial/controlflow.html#break-and-continue-statements-and-else-clauses-on-loops)
- obsługi wyjątków przy pomocy [`try..except..else..finally`](https://docs.python.org/3/tutorial/errors.html#handling-exceptions)
- kontekstu przy pomocy `with`

---

## python - instrukcje

```python
>>> i = True
>>> if i:
...     print('OK')
... else:
...     print('Bad')
... 
OK

>>> i = 2
>>> if i < 1:
...     print('Mniejsze niz 1')
... else:
...     print('Wieksze lub rowne 1')
... 
Wieksze lub rowne 1
```

---

## python - instrukcje

```python
>>> i = 1
>>> if i < 1:
...     print('Mniejsze niz 1')
... elif i > 1:
...     print('Wieksze niz 1')
... else:  # elif i == 1
...     print('Rowne 1')
... 
Rowne 1
```

---

## python - instrukcje

```python
>>> i = 1
>>> while i < 3:
...     print(i)
...     i = i + 1
... print(i)
1
2
>>> print(i)
3
```

---

## python - instrukcje

```python
>>> i = 1
>>> while i < 5:
...     print(i)
...     if i % 3 == 0:
...         print('Koncz szybciej..')
...         break
...     i = i + 1
... 
1
2
3
Koncz szybciej..
>>> print(i)
3
```

---

## python - instrukcje

```python
>>> i = 1
>>> while i < 21:
...     print(i)
...     if i % 2 == 1:
...         print('Mnoze przez 3 i dodaje 1 do %d' % i)
...         i = i * 3 + 1
...         continue
...     print('Dodaje 1 do %d' % i)
...     i = i + 1
... 
1
Mnoze przez 3 i dodaje 1 do 1
4
Dodaje 1 do 4
5
...
```

---

## python - instrukcje

```python
>>> i = 3
>>> while i < 2:
...     print(i)
... else:
...     print('Nic nie zrobilem..')
... 
Nic nie zrobilem..
```

---

## python

Odnośniki do slajdów (niektóre z tematów):

- [wyjątki](https://pasuder.github.io/labs/doc/lab02/#3)
- [blok `with`](https://pasuder.github.io/labs/doc/lab02/#6)
- [domknięcia](https://pasuder.github.io/labs/doc/lab03/#3) i [dekoratory](https://pasuder.github.io/labs/doc/lab03/#5)

Polecam zapoznać się z [tutorialem](https://docs.python.org/3/tutorial/index.html), aby uporządkować wiedzę 😃

---

## python

- cpython - podstawowa, referencyjna implementacja
- activepython
- anaconda
- ironpython
- jython
- micropython
- miniconda
- pypy
- pyston
- stackless

---

## python

### cpython

- The "traditional" implementation of Python (nicknamed CPython).
- CPython is the default byte-code interpreter of Python, which is written in C.
- [CPython](https://wiki.python.org/moin/CPython) is Guido van Rossum's reference version of the Python computing language. It's most often called simply "Python"; speakers say "CPython" generally to distinguish it explicitly from other implementations.
- [Python vs CPython](https://stackoverflow.com/q/17130975)
- It is a [Virtual stack machine](https://en.wikipedia.org/wiki/Stack_machine#Virtual_stack_machines).

---

## python

### pypy

PyPy is a replacement for CPython. It is built using the RPython language that was co-developed with it. The main reason to use it instead of CPython is speed: it runs generally faster. PyPy implements Python 2.7.13 and 3.5.3.

[Features](https://pypy.org/features.html):

- speed
- memory usage
- stackless

---

## python

### stackless

[..] named because it avoids depending on the C call stack for its own stack. [..] Stackless Python uses the C stack, but the stack is cleared between function calls. The most prominent feature of Stackless is microthreads, which avoid much of the overhead associated with usual operating system threads.

[Source](https://en.wikipedia.org/wiki/Stackless_Python) [More](https://github.com/stackless-dev/stackless/wiki)

---

## python

### jython

Jython: Python for the Java Platform.

Jython 3.x development is in progress. Jython 2.7.0 was released on May 3, 2015. Jython 2.7.1 release candidates will be released soon (September 2015).

[What is Jython?](https://wiki.python.org/jython/JythonFaq/GeneralInfo)
[Why Jython?](https://wiki.python.org/jython/WhyJython)

---

## python

### ironpython

IronPython is an excellent addition to the .NET Framework, providing Python developers with the power of the .NET framework. Existing .NET developers can also use IronPython as a fast and expressive scripting language for embedding, testing, or writing a new application from scratch.

IronPython 2.7.8 is now available! (February 16, 2018)

---

## python

- [activepython](https://www.activestate.com/products/activepython/) - [commercial version](https://wiki.python.org/moin/ActivePython)
- [anaconda](https://www.anaconda.com/) - data science
- [micropython](https://micropython.org/) - python3 for microcontrollers
- [miniconda](https://docs.conda.io/en/latest/miniconda.html) - minimal version of anaconda, without extra packages, just repo mgmt stuff
- [pyston](https://github.com/dropbox/pyston) - performance-oriented, LLVM, JIT

---

## python

Do zarządzania wersjami python na Linux: [PyEnv](https://github.com/pyenv/pyenv). Dobre dla środowisk deweloperskich.

Dla aplikacji produkcyjnych: lepiej korzystać z obrazów bazowych dla kontenerów, np.: Docker:

- https://hub.docker.com/_/python
- https://hub.docker.com/_/pypy

[Przykład Dockerfile](https://github.com/suderdev/multi-editor/blob/master/Dockerfile)

---

## python

- [(official) CPython internals](https://devguide.python.org/exploring/)
- [Python internals in short](https://medium.com/@dawranliou/getting-started-with-python-internals-a5474ccb8022)
- [Python stack machine explained](https://opensource.com/article/18/4/introduction-python-bytecode)
- [CPython internals](http://www.pgbovine.net/cpython-internals.htm)
- [Python interpreter in python](https://www.aosabook.org/en/500L/a-python-interpreter-written-in-python.html)
- [Inside The Python Virtual Machine](https://leanpub.com/insidethepythonvirtualmachine/read)

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## Inne materiały

- Książka [Algorytmy + struktury danych = programy](http://lubimyczytac.pl/ksiazka/122213/algorytmy-struktury-danych-programy)
- [Strona](http://www.algorytm.org/algorytmy/) z algorytmami i innymi rzeczami, które są (były) poruszane na WDI (Wstęp do Informatyki)
- [Ważniak](http://wazniak.mimuw.edu.pl/)
  - [Wstęp do programowania](http://wazniak.mimuw.edu.pl/index.php?title=Wst%C4%99p_do_programowania)
  - [Algorytmy i struktury danych](http://wazniak.mimuw.edu.pl/index.php?title=Algorytmy_i_struktury_danych)

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_Dziękuję!_