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How do I check (at runtime) if one class is a subclass of another?
...ple
Here is a more complete example with some assertions:
#!/usr/bin/env python3
class Base:
pass
class Derived(Base):
pass
base = Base()
derived = Derived()
# Basic usage.
assert issubclass(Derived, Base)
assert not issubclass(Base, Derived)
# True for same object.
assert issubclass(...
How to “properly” print a list?
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If you are using Python3:
print('[',end='');print(*L, sep=', ', end='');print(']')
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f...
What's the function like sum() but for multiplication? product()?
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@PatrickMcElhaney It sounds like python3 already got rid of the reduce builtin. I think product missed its chance. ;)
– ojrac
Jul 26 '16 at 14:27
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Import error: No module name urllib2
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That worked for me in python3:
import urllib.request
htmlfile = urllib.request.urlopen("http://google.com")
htmltext = htmlfile.read()
print(htmltext)
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How to search for a string in text files?
...bject rather than a string as well, eg. s.find(b'blabla'):
#!/usr/bin/env python3
import mmap
with open('example.txt', 'rb', 0) as file, \
mmap.mmap(file.fileno(), 0, access=mmap.ACCESS_READ) as s:
if s.find(b'blabla') != -1:
print('true')
You could also use regular expressions ...
How to check whether a variable is a class or not?
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Doesn't work for me. Using python3 with snakemake, type(snakemake.utils) returns <class 'module'> and yet inspect.isclass(snakemake.utils) returns False.
– tedtoal
Jul 3 '18 at 16:09
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How can I get list of values from dict?
...t.
Therefore list(dictionary.values()) is the one way.
Yet, considering Python3, what is quicker?
[*L] vs. [].extend(L) vs. list(L)
small_ds = {x: str(x+42) for x in range(10)}
small_df = {x: float(x+42) for x in range(10)}
print('Small Dict(str)')
%timeit [*small_ds.values()]
%timeit [].exten...
How to get first element in a list of tuples?
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From a performance point of view, in python3.X
[i[0] for i in a] and list(zip(*a))[0] are equivalent
they are faster than list(map(operator.itemgetter(0), a))
Code
import timeit
iterations = 100000
init_time = timeit.timeit('''a = [(i, u'abc') for i in ra...
Format a datetime into a string with milliseconds
...t;>>> OUTPUT >>>>
2020-05-04 10:18:32.926
Note: For Python3, print requires parentheses:
print(datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S.%f')[:-3])
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SQLAlchemy - Getting a list of tables
...e.table_names()) File "/Users/darshanchoudhary/.virtualenvs/services/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 2128, in table_names return self.dialect.get_table_names(conn, schema) value = value.replace(self.escape_quote, self.escape_to_quote) AttributeError: 'NoneType'...