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Add example: The surprising comma
Closes https://github.com/satwikkansal/wtfpython/issues/1
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README.md
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README.md
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@ -1481,6 +1481,38 @@ tuple()
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---
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### The surprising comma
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Suggested by @MostAwesomeDude in [this](https://github.com/satwikkansal/wtfPython/issues/1) issue.
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**Output:**
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```py
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>>> def f(x, y,):
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... print(x, y)
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...
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>>> def g(x=4, y=5,):
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... print(x, y)
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...
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>>> def h(x, **kwargs,):
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File "<stdin>", line 1
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def h(x, **kwargs,):
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^
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SyntaxError: invalid syntax
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>>> def h(*args,):
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File "<stdin>", line 1
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def h(*args,):
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^
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SyntaxError: invalid syntax
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```
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#### 💡 Explanation:
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- Trailing comma is not always legal in formal parameters list of a Python function.
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- In Python, the argument list is defined partially with leading commas and partially with trailing commas. This conflict causes situations where a comma is trapped in the middle, and no rule accepts it.
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- **Note:** The trailing comma problem is [fixed in Python 3.6](https://bugs.python.org/issue9232). The remarks in [this](https://bugs.python.org/issue9232#msg248399) post discuss in brief different usages of trailing commas in Python.
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---
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### For what?
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Suggested by @MittalAshok in [this](https://github.com/satwikkansal/wtfpython/issues/23) issue.
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