Why one can't pass 'parent' and 'tag' arguments as kwargs to SubElement factory function of...
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I'm using Python 3.6.5. What works:
from xml.etree.ElementTree import Element, SubElement
root = Element("root")
SubElement(root, "sub")
what doesn't:
from xml.etree.ElementTree import Element, SubElement
root = Element("root")
SubElement(parent=root, tag="sub")
So the only difference is passing parent and tag as keyword arguments (with proper keywords, mind you). Also look at the stack trace:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: SubElement() takes at least 2 arguments (0 given)
How on Earth there were 0 arguments given?
A look at the source for SubElement: lines 443:459 hasn't struck me with any revelations. As you can see the two positional parameters of SubElement are indeed named parent and tag.
Are we to have second thoughts about validity of this particular Raymond Hettinger's piece of advice?
python arguments parameter-passing elementtree keyword-argument
asked Nov 22 at 13:43
z33k
307413
add a comment |
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0
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I'm using Python 3.6.5. What works:
from xml.etree.ElementTree import Element, SubElement
root = Element("root")
SubElement(root, "sub")
what doesn't:
from xml.etree.ElementTree import Element, SubElement
root = Element("root")
SubElement(parent=root, tag="sub")
So the only difference is passing parent and tag as keyword arguments (with proper keywords, mind you). Also look at the stack trace:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: SubElement() takes at least 2 arguments (0 given)
How on Earth there were 0 arguments given?
A look at the source for SubElement: lines 443:459 hasn't struck me with any revelations. As you can see the two positional parameters of SubElement are indeed named parent and tag.
Are we to have second thoughts about validity of this particular Raymond Hettinger's piece of advice?
python arguments parameter-passing elementtree keyword-argument
asked Nov 22 at 13:43
z33k
307413
What Python version are you using, and if 2.x, which encoding? (Note, that XML always needs unicode).
– guidot
Nov 22 at 14:17
Added the Python version used. Encoding shouldn't be an issue at this stage (we're not dumping to file anything yet)
– z33k
Nov 22 at 14:53
1
In Python 2.7, you can pass 'parent' and 'tag' as keyword arguments.
– mzjn
Nov 23 at 6:58
1
When using lxml instead of ElementTree, there is a slightly different error message (both Python 2 and Python 3): "TypeError: SubElement() takes at least 2 positional arguments (0 given)".
– mzjn
Nov 23 at 6:58
Now that's illuminating. What could be the design reasons for enforcing using only positional arguments on users? Fear about the user making a typo? (Then the arguments would be gobbled up by**extra)
– z33k
Nov 23 at 9:30
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
I'm using Python 3.6.5. What works:
from xml.etree.ElementTree import Element, SubElement
root = Element("root")
SubElement(root, "sub")
what doesn't:
from xml.etree.ElementTree import Element, SubElement
root = Element("root")
SubElement(parent=root, tag="sub")
So the only difference is passing parent and tag as keyword arguments (with proper keywords, mind you). Also look at the stack trace:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: SubElement() takes at least 2 arguments (0 given)
How on Earth there were 0 arguments given?
A look at the source for SubElement: lines 443:459 hasn't struck me with any revelations. As you can see the two positional parameters of SubElement are indeed named parent and tag.
Are we to have second thoughts about validity of this particular Raymond Hettinger's piece of advice?
python arguments parameter-passing elementtree keyword-argument
asked Nov 22 at 13:43
z33k
307413
I'm using Python 3.6.5. What works:
from xml.etree.ElementTree import Element, SubElement
root = Element("root")
SubElement(root, "sub")
what doesn't:
from xml.etree.ElementTree import Element, SubElement
root = Element("root")
SubElement(parent=root, tag="sub")
So the only difference is passing parent and tag as keyword arguments (with proper keywords, mind you). Also look at the stack trace:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: SubElement() takes at least 2 arguments (0 given)
How on Earth there were 0 arguments given?
A look at the source for SubElement: lines 443:459 hasn't struck me with any revelations. As you can see the two positional parameters of SubElement are indeed named parent and tag.
Are we to have second thoughts about validity of this particular Raymond Hettinger's piece of advice?
python arguments parameter-passing elementtree keyword-argument
python arguments parameter-passing elementtree keyword-argument
asked Nov 22 at 13:43
z33k
307413
asked Nov 22 at 13:43
z33k
307413
edited Nov 22 at 14:51
asked Nov 22 at 13:43
z33k
307413
asked Nov 22 at 13:43
z33k
307413
asked Nov 22 at 13:43
z33k
307413
307413
What Python version are you using, and if 2.x, which encoding? (Note, that XML always needs unicode).
– guidot
Nov 22 at 14:17
Added the Python version used. Encoding shouldn't be an issue at this stage (we're not dumping to file anything yet)
– z33k
Nov 22 at 14:53
1
In Python 2.7, you can pass 'parent' and 'tag' as keyword arguments.
– mzjn
Nov 23 at 6:58
1
When using lxml instead of ElementTree, there is a slightly different error message (both Python 2 and Python 3): "TypeError: SubElement() takes at least 2 positional arguments (0 given)".
– mzjn
Nov 23 at 6:58
Now that's illuminating. What could be the design reasons for enforcing using only positional arguments on users? Fear about the user making a typo? (Then the arguments would be gobbled up by**extra)
– z33k
Nov 23 at 9:30
add a comment |
What Python version are you using, and if 2.x, which encoding? (Note, that XML always needs unicode).
– guidot
Nov 22 at 14:17
Added the Python version used. Encoding shouldn't be an issue at this stage (we're not dumping to file anything yet)
– z33k
Nov 22 at 14:53
1
In Python 2.7, you can pass 'parent' and 'tag' as keyword arguments.
– mzjn
Nov 23 at 6:58
1
When using lxml instead of ElementTree, there is a slightly different error message (both Python 2 and Python 3): "TypeError: SubElement() takes at least 2 positional arguments (0 given)".
– mzjn
Nov 23 at 6:58
Now that's illuminating. What could be the design reasons for enforcing using only positional arguments on users? Fear about the user making a typo? (Then the arguments would be gobbled up by**extra)
– z33k
Nov 23 at 9:30
What Python version are you using, and if 2.x, which encoding? (Note, that XML always needs unicode).
– guidot
Nov 22 at 14:17
What Python version are you using, and if 2.x, which encoding? (Note, that XML always needs unicode).
– guidot
Nov 22 at 14:17
Added the Python version used. Encoding shouldn't be an issue at this stage (we're not dumping to file anything yet)
– z33k
Nov 22 at 14:53
Added the Python version used. Encoding shouldn't be an issue at this stage (we're not dumping to file anything yet)
– z33k
Nov 22 at 14:53
1
1
In Python 2.7, you can pass 'parent' and 'tag' as keyword arguments.
– mzjn
Nov 23 at 6:58
In Python 2.7, you can pass 'parent' and 'tag' as keyword arguments.
– mzjn
Nov 23 at 6:58
1
1
When using lxml instead of ElementTree, there is a slightly different error message (both Python 2 and Python 3): "TypeError: SubElement() takes at least 2 positional arguments (0 given)".
– mzjn
Nov 23 at 6:58
When using lxml instead of ElementTree, there is a slightly different error message (both Python 2 and Python 3): "TypeError: SubElement() takes at least 2 positional arguments (0 given)".
– mzjn
Nov 23 at 6:58
Now that's illuminating. What could be the design reasons for enforcing using only positional arguments on users? Fear about the user making a typo? (Then the arguments would be gobbled up by
**extra)– z33k
Nov 23 at 9:30
Now that's illuminating. What could be the design reasons for enforcing using only positional arguments on users? Fear about the user making a typo? (Then the arguments would be gobbled up by
**extra)– z33k
Nov 23 at 9:30
add a comment |
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What Python version are you using, and if 2.x, which encoding? (Note, that XML always needs unicode).
– guidot
Nov 22 at 14:17
Added the Python version used. Encoding shouldn't be an issue at this stage (we're not dumping to file anything yet)
– z33k
Nov 22 at 14:53
1
In Python 2.7, you can pass 'parent' and 'tag' as keyword arguments.
– mzjn
Nov 23 at 6:58
1
When using lxml instead of ElementTree, there is a slightly different error message (both Python 2 and Python 3): "TypeError: SubElement() takes at least 2 positional arguments (0 given)".
– mzjn
Nov 23 at 6:58
Now that's illuminating. What could be the design reasons for enforcing using only positional arguments on users? Fear about the user making a typo? (Then the arguments would be gobbled up by
**extra)– z33k
Nov 23 at 9:30