Use this tag for questions related with argument unpacking, a technique that allows Arrays and Traversable objects to be extracted/unpacked into argument lists/sequences.
argument-unpacking is usually found in PHP, Python and Go.
Questions tagged [argument-unpacking]
144 questions
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Input each element of a list into a function in python
Suppose I have a list l=[A,B,C,D] and a pre-defined funcion (I am using sympy.solve_linear_system(matrix,A,B,C,D). I want to evaluate the function without writing in A,B,C,D. I want to do it in terms of the list. Is this possible?
When I use Unpack…
Jake McNaughton
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1 answer
Does * Unpacking Use Memory on Generator Expression?
Example for context:
Does calling * to unpack input put everything into memory? I'm hoping not but just want to confirm my understanding.
input = (x for x in ((1, 'abc'), (2, 'def'))) # generator expression
unzipped = zip(*input) # Does *input get…
aksg87
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How to print unpacked iterable or string?
I am trying to print a unpacked iterable, or a string if said iterable is empty in Python 3.9 (also happens in 3.10), and I am getting some unexpected behavior. print is applying the star operator to the whole Iterable or str expression, regardless…
walkerfinlay
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1 answer
Passing a dictionary to a function with unpacking argument
This below snippet of code gives me this error TypeError: pop() argument after ** must be a mapping, not tuple.
class a():
data={'a':'aaa','b':'bbb','c':'ccc'}
def pop(self, key, **args):
return self.data.pop(key,…
Kumar
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1 answer
Printing a tuple in Python using both "for" loop and unpacking with star operator (*)
I am trying to print the items of the "result" tuple in the following code in 2 different ways:
using a "for" loop
using a star operator in the print() method
In the output, the string "reference point" is supposed to separate the results of the…
Marios
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- 2
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2 answers
How to make it one-liner? Convert list to a bunch of parameters
I have the following code:
from datetime import datetime
ds = "2020.10.10.12.30.59"
y, M, d, h, m, s = [int(x) for x in ds.split('.')]
dt = datetime(y, M, d, h, m, s)
print(dt)
I would like to make it to one-liner something like this:
dt =…
pvoj
- 339
- 3
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0
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1 answer
how to pack my numpy variables and arrays when calling curve_fit?
This is my standalone code to reproduce the problem:
import numpy as np
from scipy.optimize import curve_fit
def find_vector_of_minor_axis_from_chunk(data):
n = 20 # number of points
time = np.linspace(0, 2 * np.pi, n)
…
Andreas Schuldei
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0
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1 answer
Typescript unpacking arguments to overloaded function
Just to illustrate what I mean by "unpacking", consider the following example
function simpleFunc(a: number, b: string): void { /* ... */ }
function simpleProxy(args: [number, string]) {
simpleFunc(...args)
}
This works just fine, with…
Antoine
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1 answer
not enough values to unpack (expected 2, got 1) adaboost algorithm
def adaboost(X_train, Y_train, X_test, Y_test, lamb=0.01, num_iterations=200, learning_rate=0.001):
label_train = 2*Y_train -1
label_test = 2*Y_test -1
[n,p] = X_train.shape
[ntest, ptest] = X_test.shape
X_train_1 =…
Rad
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0
votes
2 answers
A Python function that interleaves arbitrary number of lists as parameters
Edited for the sake of simplicity, as I have pin pointed the issue to 'argument unpacking'.
I am trying to write a function that interleaves an arbitrary number of lists as parameters. All the lists have equal length. The function should return one…
Saurus
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0
votes
1 answer
Packing keyword arguments in Racket?
Is there a way to specify keyword arguments to a function as a dictionary, analogously to the . that allows us to supply a list for positional arguments? I'm looking for something analogous to python's *args and **kwargs.
In more detail:
If we want…
mindthief
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1 answer
Invalid unpacking arguments
I was reading an online document explaining unpacking (*args and **kwargs). Getting confused by the following two asserts, not sure why the second function is invalid. Could anyone help me to understand the reason?
def f(x, y, z):
return [x, y,…
r0n9
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1 answer
Unpacking Python Dictionary of Various Length into sql query
I currently have a function which takes a dictionary as an input and returns all columns in database table as a dict:
import sqlite3
def get_person_dict_from_dict(self):
database = "/Users/Mary/Documents/Database/{DB}.db".format(DB=self['db'])
…
Mary
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1 answer
Unpacking set in string format in python only returns first value
I have converted a DataFrame Column into a set, and I am trying to format the values into a string using the * to unpack it like a list. However, it only returns the first value.
I am using the python-docx to automatically create reports based on…
CenturionNOR
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0
votes
1 answer
Specifying arguments in a function from a list
I've read up on a number of threads (here and here) and the docs (here and here). However, I can't get this to work. I get an error of
AxisError: axis 0 is out of bounds for array of dimension 0
Thanks.
import pandas as pd
from scipy.stats import…
June
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