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Use cases for the 'setdefault' dict method
... but not so much if it's dynamic.
For example, I need a dictionary to map strings to unique ints. defaultdict(int) will always use 0 for the default value. Likewise, defaultdict(intGen()) always produces 1.
Instead, I used a regular dict:
nextID = intGen()
myDict = {}
for lots of complicated stuf...
How to rename a file using Python
... as well:
ext = p.suffix
We can perform our modification with a simple string manipulation:
Python 3.6 and greater make use of f-strings!
new_file_name = f"{name_without_extension}_1"
Otherwise:
new_file_name = "{}_{}".format(name_without_extension, 1)
And now we can perform our rename by...
How to sort in mongoose?
... mongoose 3 you can't use Array for field selection anymore - it has to be String or Object
– pkyeck
Oct 14 '12 at 7:30
4
...
How to access object attribute given string corresponding to name of that attribute
...this and say i have a dataframe df1,and a variable x = 'df1' i.e. df1 as a string in var x. i want to print the shape of df like this, getattr(x, 'shape') or getattr('df1', 'shape'). I know this cannot be done with getattr, any other methods.
– ihightower
Feb 1...
ImportError: Cannot import name X
...es that have not been defined yet, that
definition may be expressed as a string literal, to be resolved later.
and remove the dependency (the import), e.g. instead of
from my_module import Tree
def func(arg: Tree):
# code
do:
def func(arg: 'Tree'):
# code
(note the removed import ...
Why should hash functions use a prime number modulus?
... by taking the "component parts" of the input (characters in the case of a string), and multiplying them by the powers of some constant, and adding them together in some integer type. So for example a typical (although not especially good) hash of a string might be:
(first char) + k * (second char)...
json.dumps vs flask.jsonify
...understand the purpose of the flask.jsonify method. I try to make a JSON string from this:
5 Answers
...
How to extract a substring using regex
I have a string that has two single quotes in it, the ' character. In between the single quotes is the data I want.
13 An...
Best way to give a variable a default value (simulate Perl ||, ||= )
...specific to a null value. For example, if $_GET['name'] is set to an empty string, the first line would return an empty string, but we could return "john doe" by using $_GET['name'] ? $_GET['name'] : 'john doe'.
– VPhantom
May 20 at 18:33
...
What happens to an open file handle on Linux if the pointed file gets moved or deleted
...ntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <strings.h>
#include <stdio.h>
void perror_and_exit() {
perror(NULL);
exit(1);
}
int main(int argc, char *argv[]) {
int fd;
if ((fd = open("data", O_RDONLY)) == -1) {
perror_and_exit();
}
char buf[5]...