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Commit46fc2fa

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default value & typing hint dataclasses
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‎README.md‎

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@@ -198,6 +198,8 @@ All contributions are welcome:
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-[setup.py](#setuppy)
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-[Dataclasses](#dataclasses)
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-[Features](#features)
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-[Default values](#default-values)
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-[Type hints](#type-hints)
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-[Virtual Environment](#virtual-environment)
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-[virtualenv](#virtualenv)
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-[pipenv](#pipenv)
@@ -539,26 +541,26 @@ The *and* Operator’s *Truth* Table:
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| Expression| Evaluates to|
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| -----------------| ------------|
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|`True and True`|`True`|
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|`True and False`|`False`|
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|`False and True`|`False`|
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|`False and False`|`False`|
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|`True and True`|`True`|
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|`True and False`|`False`|
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|`False and True`|`False`|
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|`False and False`|`False`|
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The*or* Operator’s*Truth* Table:
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| Expression| Evaluates to|
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| ----------------| --------------|
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|`True or True`|`True`|
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|`True or False`|`True`|
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|`False or True`|`True`|
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|`False or False`|`False`|
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| Expression| Evaluates to|
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| ----------------| ------------|
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|`True or True`|`True`|
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|`True or False`|`True`|
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|`False or True`|`True`|
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|`False or False`|`False`|
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The*not* Operator’s*Truth* Table:
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| Expression| Evaluates to|
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| ------------|-------------|
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|`not True`|`False`|
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|`not False`|`True`|
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| Expression| Evaluates to|
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| -----------| ------------|
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|`not True`|`False`|
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|`not False`|`True`|
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[*Return to the Top*](#python-cheatsheet)
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### Escape Characters
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| Escape character| Printsas|
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|------------------|--------------------|
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|`\'`| Single quote |
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| `\"`| Double quote |
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|`\t`| Tab |
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| `\n`| Newline (line break) |
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|`\\`| Backslash |
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| Escape character| Printsas|
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|----------------|--------------------|
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|`\'` | Single quote |
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| `\"` | Double quote |
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|`\t` | Tab |
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| `\n` | Newline (line break) |
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|`\\` | Backslash |
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Example:
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|`\d`, `\w`, and `\s` | a digit, word, or space character, ectively. |
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| `\D`, `\W`, and `\S` | anything except a digit, word, or space acter, respectively. |
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|`[abc]`|any character between the brackets (suchas a, b, ).|
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|`[^abc]`|any character that isn’t between the brackets.|
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|`[^abc]`|any character that isn’t between the brackets.|
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[*Return to the Top*](#python-cheatsheet)
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@@ -4115,7 +4117,7 @@ Logging levels provide a way to categorize your log messages by importance. Ther
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|----------|--------------------|------------------------------------------------------------------------------------------------------------------------------|
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|`DEBUG`|`logging.debug()`| The lowest level. Usedfor small details. Usually you care about these messages only when diagnosing problems.|
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|`INFO`|`logging.info()`| Used to record information on general eventsin your programor confirm that things are working at their pointin the program.|
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|`WARNING`|`logging.warning()`| Used to indicate a potential problem that doesn’t prevent the programfrom working but might do soin the future.|
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|`WARNING`|`logging.warning()`| Used to indicate a potential problem that doesn’t prevent the programfrom working but might do soin the future.|
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|`ERROR`|`logging.error()`| Used to record an error that caused the program to fail to do something.|
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|`CRITICAL`|`logging.critical()`| The highest level. Used to indicate a fatal error that has causedoris about to cause the program to stop running entirely.|
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@@ -4494,6 +4496,43 @@ with dataclass
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[*Return to the Top*](#python-cheatsheet)
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### Default values
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Itis easy to add default values to the fields of your dataclass.
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```python
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>>>@dataclass
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...class Product:
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... name:str
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... count:int=0
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... price:float=0.0
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...
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>>>obj= Product("Python")
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>>> obj.name
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Python
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>>> obj.count
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0
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>>> obj.price
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0.0
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```
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### Type hints
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Itis mandatory to define the datatypein dataclass. However, If you don't want specify the datatype then, use ```typing.Any```.
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```python
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>>>from dataclassesimport dataclass
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>>>from typingimport Any
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>>>@dataclass
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...class WithoutExplicitTypes:
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... name: Any
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... value:Any=42
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...
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```
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[*Return to the Top*](#python-cheatsheet)
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## Virtual Environment
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The use of a Virtual Environmentis to test python codein encapsulated environmentsand to also avoid filling the base Python installationwith libraries we might usefor only one project.

‎blog_files/pysheet.md‎

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>>> obj.val
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2
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```
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### Default values
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Itis easy to add default values to the fields of your dataclass.
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... name: Any
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... value:Any=42
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...
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```
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```
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## Virtual Environment
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‎python_cheat_sheet.ipynb‎

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"- [setup.py](#setuppy)\n",
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"- [Dataclasses](#dataclasses)\n",
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" - [Features](#features)\n",
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" - [Default values](#default-values)\n",
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" - [Type hints](#type-hints)\n",
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"- [Virtual Environment](#virtual-environment)\n",
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" - [virtualenv](#virtualenv)\n",
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" - [pipenv](#pipenv)\n",
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"\n",
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"| Expression | Evaluates to |\n",
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"| ----------------- | ------------ |\n",
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"| `True and True` | `True` |\n",
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"| `True and False` | `False` |\n",
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"| `False and True` | `False` |\n",
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"| `False and False` | `False` |\n",
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"| `True and True` | `True`|\n",
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"| `True and False` | `False`|\n",
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"| `False and True` | `False`|\n",
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"| `False and False` | `False`|\n",
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"\n",
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"The *or* Operator’s *Truth* Table:\n",
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"\n",
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"| Expression | Evaluates to|\n",
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"| ---------------- | -------------- |\n",
858-
"| `True or True` | `True`|\n",
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"| `True or False` | `True`|\n",
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"| `False or True` | `True`|\n",
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"| `False or False` | `False`|\n",
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"| Expression | Evaluates to |\n",
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"| ---------------- | ------------ |\n",
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"| `True or True` | `True` |\n",
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"| `True or False` | `True` |\n",
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"| `False or True` | `True` |\n",
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"| `False or False` | `False` |\n",
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"\n",
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"The *not* Operator’s *Truth* Table:\n",
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"\n",
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"| Expression| Evaluates to |\n",
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"| ------------ |------------- |\n",
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"| `not True`| `False` |\n",
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"| `not False`| `True` |\n",
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"| Expression | Evaluates to |\n",
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"| ----------- | ------------ |\n",
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"| `not True` | `False` |\n",
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"| `not False` | `True` |\n",
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"\n",
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"[*Return to the Top*](#python-cheatsheet)\n",
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"\n",
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"\n",
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"### Escape Characters\n",
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"\n",
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"| Escape character| Prints as |\n",
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"| ------------------ | -------------------- |\n",
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"| `\\'`| Single quote |\n",
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"| `\\\"`| Double quote |\n",
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"| `\\t`| Tab |\n",
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"| `\\n`| Newline (line break) |\n",
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"| `\\\\`| Backslash |\n",
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"| Escape character | Prints as |\n",
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"| ---------------- | -------------------- |\n",
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"| `\\'` | Single quote |\n",
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"| `\\\"` | Double quote |\n",
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"| `\\t` | Tab |\n",
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"| `\\n` | Newline (line break) |\n",
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"| `\\\\` | Backslash |\n",
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"\n",
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"Example:"
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]
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"| `\\d`, `\\w`, and `\\s` | a digit, word, or space character, ectively. |\n",
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"| `\\D`, `\\W`, and `\\S` | anything except a digit, word, or space acter, respectively. |\n",
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"| `[abc]` | any character between the brackets (such as a, b, ). |\n",
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"| `[^abc]` | any character that isn’t between the brackets.|\n",
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"| `[^abc]` | any character that isn’t between the brackets. |\n",
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"\n",
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"[*Return to the Top*](#python-cheatsheet)\n",
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"\n",
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"| ---------- | -------------------- | ------------------------------------------------------------------------------------------------------------------------------ |\n",
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"| `DEBUG` | `logging.debug()` | The lowest level. Used for small details. Usually you care about these messages only when diagnosing problems. |\n",
70597061
"| `INFO` | `logging.info()` | Used to record information on general events in your program or confirm that things are working at their point in the program. |\n",
7060-
"| `WARNING` | `logging.warning()` | Used to indicate a potential problem that doesn’t prevent the program from working but might do so in the future.|\n",
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"| `WARNING` | `logging.warning()` | Used to indicate a potential problem that doesn’t prevent the program from working but might do so in the future. |\n",
70617063
"| `ERROR` | `logging.error()` | Used to record an error that caused the program to fail to do something. |\n",
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"| `CRITICAL` | `logging.critical()` | The highest level. Used to indicate a fatal error that has caused or is about to cause the program to stop running entirely. |\n",
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"\n",
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"2"
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]
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},
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{
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"cell_type":"markdown",
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"metadata": {},
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"source": [
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"[*Return to the Top*](#python-cheatsheet)\n",
7658+
"\n",
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"### Default values\n",
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"\n",
7661+
"It is easy to add default values to the fields of your data class."
7662+
]
7663+
},
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{
7665+
"cell_type":"code",
7666+
"execution_count":null,
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"metadata": {},
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"outputs": [],
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"source": [
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">>> @dataclass\n",
7671+
"... class Product:\n",
7672+
"... name: str\n",
7673+
"... count: int = 0\n",
7674+
"... price: float = 0.0\n",
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"...\n",
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">>> obj = Product(\"Python\")\n",
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">>> obj.name\n",
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"Python\n",
7679+
">>> obj.count\n",
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"0\n",
7681+
">>> obj.price\n",
7682+
"0.0"
7683+
]
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},
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{
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"cell_type":"markdown",
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"metadata": {},
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"source": [
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"### Type hints\n",
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"\n",
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"It is mandatory to define the data type in dataclass. However, If you don't want specify the datatype then, use ```typing.Any```."
7692+
]
7693+
},
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{
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"cell_type":"code",
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"execution_count":null,
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"metadata": {},
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"outputs": [],
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"source": [
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">>> from dataclasses import dataclass\n",
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">>> from typing import Any\n",
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"\n",
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">>> @dataclass\n",
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"... class WithoutExplicitTypes:\n",
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"... name: Any\n",
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"... value: Any = 42\n",
7707+
"..."
7708+
]
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},
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{
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"cell_type":"markdown",
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"metadata": {},

‎python_cheat_sheet.pdf‎

3.49 KB
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