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Python __call__ special method practical example
...torial function that contains a static variable (as that's not possible in Python).
class Factorial:
def __init__(self):
self.cache = {}
def __call__(self, n):
if n not in self.cache:
if n == 0:
self.cache[n] = 1
else:
...
How to print a linebreak in a python function?
I have a list of strings in my code;
8 Answers
8
...
Reading specific lines only
... 29:
break
fp.close()
Note that i == n-1 for the nth line.
In Python 2.6 or later:
with open("file") as fp:
for i, line in enumerate(fp):
if i == 25:
# 26th line
elif i == 29:
# 30th line
elif i > 29:
break
...
How do I check if a string is a number (float)?
...e best possible way to check if a string can be represented as a number in Python?
33 Answers
...
Copy to clipboard in Node.js?
...e of node-copy-paste, it calls out to pbcopy/pbpaste (for OSX), xclip (for linux), and clip (for windows).
This module was very helpful when I was doing a lot of work in the REPL for a side project. Needless to say, copy-paste is only a command line utility -- it is not meant for server work.
...
Check if multiple strings exist in another string
...
any() takes an iterable. I am not sure which version of Python you are using but in 2.6 you will need to put [] around your argument to any(). any([x in str for x in a]) so that the comprehension returns an iterable. But maybe later versions of Python already do this.
...
How do I get a list of column names from a psycopg2 cursor?
...umn labels directly from the selected column names, and recall seeing that python's psycopg2 module supports this feature.
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Difference between two dates in Python
...imedelta object and the documentation makes not mention of it either (docs.python.org/2/library/datetime.html).
– user1761806
Jun 26 '17 at 10:46
4
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TypeError: method() takes 1 positional argument but 2 were given
...
In Python, this:
my_object.method("foo")
...is syntactic sugar, which the interpreter translates behind the scenes into:
MyClass.method(my_object, "foo")
...which, as you can see, does indeed have two arguments - it's just...
In Python how should I test if a variable is None, True or False
...
Agreed. Much more pythonic than the evidently more popular solution above (which smells too much like C code).
– Brandon
Jan 7 '10 at 13:53
...