np.put places values from b into a at the target indices, ind. If v is shorter than ind, its values are repeated as necessary:
import numpy as np
a = np.empty(100)
b = np.arange(1, 4, 0.25)
ind = np.arange(len(a))
np.put(a, ind, b)
print(a)
yields
[ 1. 1.25 1.5 1.75 2. 2.25 2.5 2.75 3. 3.25 3.5 3.75
1. 1.25 1.5 1.75 2. 2.25 2.5 2.75 3. 3.25 3.5 3.75
1. 1.25 1.5 1.75 2. 2.25 2.5 2.75 3. 3.25 3.5 3.75
1. 1.25 1.5 1.75 2. 2.25 2.5 2.75 3. 3.25 3.5 3.75
1. 1.25 1.5 1.75 2. 2.25 2.5 2.75 3. 3.25 3.5 3.75
1. 1.25 1.5 1.75 2. 2.25 2.5 2.75 3. 3.25 3.5 3.75
1. 1.25 1.5 1.75 2. 2.25 2.5 2.75 3. 3.25 3.5 3.75
1. 1.25 1.5 1.75 2. 2.25 2.5 2.75 3. 3.25 3.5 3.75
1. 1.25 1.5 1.75]
Top answer 1 of 3
8
np.put places values from b into a at the target indices, ind. If v is shorter than ind, its values are repeated as necessary:
import numpy as np
a = np.empty(100)
b = np.arange(1, 4, 0.25)
ind = np.arange(len(a))
np.put(a, ind, b)
print(a)
yields
[ 1. 1.25 1.5 1.75 2. 2.25 2.5 2.75 3. 3.25 3.5 3.75
1. 1.25 1.5 1.75 2. 2.25 2.5 2.75 3. 3.25 3.5 3.75
1. 1.25 1.5 1.75 2. 2.25 2.5 2.75 3. 3.25 3.5 3.75
1. 1.25 1.5 1.75 2. 2.25 2.5 2.75 3. 3.25 3.5 3.75
1. 1.25 1.5 1.75 2. 2.25 2.5 2.75 3. 3.25 3.5 3.75
1. 1.25 1.5 1.75 2. 2.25 2.5 2.75 3. 3.25 3.5 3.75
1. 1.25 1.5 1.75 2. 2.25 2.5 2.75 3. 3.25 3.5 3.75
1. 1.25 1.5 1.75 2. 2.25 2.5 2.75 3. 3.25 3.5 3.75
1. 1.25 1.5 1.75]
2 of 3
5
updating solution to fit description
a = np.empty(100)
filler = np.arange(1,4,0.25)
index = np.arange(a.size)
np.put(a,index,filler)
AskPython
askpython.com › python › array › initialize-a-python-array
3 Ways to Initialize an Array in Python - AskPython
3 weeks ago - When filling the array with a range, generate values with np.arange() and reshape only when the element count matches the target dimensions. For example, six values fit shape (2, 3).
Filling an array in python - Stack Overflow
I tried to create a new array and then fill it with for or while loop, but I can't get it fully filled. How can I do it in numpy with python without filling it manually? More on stackoverflow.com
python - How to fill a list - Stack Overflow
These create new lists instead of "filling" lists like the OP wanted. Another Pythonic way to achieve the first two would be to unpack range object with [*range(3)] and multiply a list of int with [-1] * 3. More on stackoverflow.com
How to fill a matrix using numpy
There's lots of ways to fill arrays. Here are some examples: import numpy as np arr = np.empty((3, 4)) # Value by value for i in range(arr.shape[0]): for j in range(arr.shape[1]): arr[i, j] = i + j # Row by row for i in range(arr.shape[0]): row = range(arr.shape[1]) arr[i, :] = row # Column by column for j in range(arr.shape[1]): row = range(arr.shape[0]) arr[:, j] = row # Or just all at once arr = np.array([ [1, 2, 3], [4, 5, 6], [7, 8, 9] ]) # Or use one of many built-in functions arr = np.arange(3 * 4).reshape(3, 4) More on reddit.com
3
2
June 18, 2020Python - Filling an array with calculated values - Stack Overflow
Why are you using a nested for loop to fill the information? The for i in range(0, len(x), 1) seems unnecessary. ... Thank you! Your solutions worked to perfection. ... If the f2 is a lambda or a function that applies calculations to a variable, it might be possible to apply that function to the entire array without ... More on stackoverflow.com
How do I initialize an array in Python with a size?
For a general one-dimensional sequence, use a list such as [None] * size or [0] * size. For a NumPy array, pass a length or shape tuple to a creation function such as np.zeros() or np.full().
askpython.com
askpython.com › python › array › initialize-a-python-array
3 Ways to Initialize an Array in Python - AskPython
How do I initialize a 2D NumPy array with zeros?
Pass a tuple containing the row and column counts to np.zeros(), such as np.zeros((2, 3)). Specify dtype when the default floating-point type is not what you want.
askpython.com
askpython.com › python › array › initialize-a-python-array
3 Ways to Initialize an Array in Python - AskPython
Does np.empty() create an array of zeros?
No. Numeric entries from np.empty() are uninitialized and may contain arbitrary values. Assign them before reading, or use np.zeros() when zero values are required.
askpython.com
askpython.com › python › array › initialize-a-python-array
3 Ways to Initialize an Array in Python - AskPython
Top answer 1 of 2
3
arr = np.zeros(10)
arr[4:7] = 1
print(arr)
Output:
array([0., 0., 0., 0., 1., 1., 1., 0., 0., 0.])
2 of 2
0
For computed ranges slices are quite useful:
ar = np.zeros(3*6).reshape((3,6))
for i in range(3):
ar[i, slice(i+1,i+3)] = 1
print(ar)
Output:
[[0. 1. 1. 0. 0. 0.]
[0. 0. 1. 1. 0. 0.]
[0. 0. 0. 1. 1. 0.]]
Also, these allow specification of stride (step) values:
ar = np.zeros(2*10).reshape((2,10))
for i in range(2):
ar[i, slice(i+1, i+8, 2)] = 2-i
print(ar)
Output:
[[0. 2. 0. 2. 0. 2. 0. 2. 0. 0.]
[0. 0. 1. 0. 1. 0. 1. 0. 1. 0.]]
Top answer 1 of 4
4
Using np.repeat and np.tile on x and y respectively to get the desired columns and then stacking them together with z into one array:
Use with AIimport numpy as np
x = [1, 2, 3]
y = [4, 5]
z = [6, 7, 8, 9, 10, 11]
a = np.array([np.repeat(x, 2), np.tile(y, 3), z]).T
result:
Use with AIarray([[ 1, 4, 6],
[ 1, 5, 7],
[ 2, 4, 8],
[ 2, 5, 9],
[ 3, 4, 10],
[ 3, 5, 11]])
2 of 4
3
For a pure Python solution, to work with any list size.
Use with AIx = [11,12,13,14,15]
y = [21,23,24]
z = [31,32,33,34,35,36,37]
This verbose code:
Use with AItmp = []
for i in range(max(len(x), len(y), len(z))):
for yy in y:
tmp.append([x[i%len(x)], yy])
for i in range(len(tmp)):
tmp[i].append((z[i%len(z)]))
Returns
Use with AI# [[11, 21, 31],
# [11, 23, 32],
# [11, 24, 33],
# [12, 21, 34],
# [12, 23, 35],
# [12, 24, 36],
# [13, 21, 37],
# [13, 23, 31],
# [13, 24, 32],
# [14, 21, 33],
# [14, 23, 34],
# [14, 24, 35],
# [15, 21, 36],
# [15, 23, 37],
# [15, 24, 31],
# [11, 21, 32],
# [11, 23, 33],
# [11, 24, 34],
# [12, 21, 35],
# [12, 23, 36],
# [12, 24, 37]]
Java2Blog
java2blog.com › home › python › python array › fill array with random numbers in python
Fill Array with Random Numbers in Python - Java2Blog
June 27, 2022 - The randint() function can be used to generate an array of the required size and fill array with random numbers in Python. We need to remember the three main parameters. The first two parameters are the low and high values. The function will select a random integer between this range.
Top answer 1 of 6
25
Consider the usage of extend:
>>> l = [] >>> l.extend(range(1, 6)) >>> print l [1, 2, 3, 4, 5] >>> l.extend(range(1, 6)) >>> print l [1, 2, 3, 4, 5, 1, 2, 3, 4, 5]
If you want to make a function (doing the same):
def fillmylist(l, n):
l.extend(range(1, n + 1))
l = []
fillmylist(l, 5)
2 of 6
4
A function without an explicit return or yield returns None. What you want is
def fill_list(l, n):
for i in xrange(1, n+1):
l.append(i)
return l
but that's very unpythonic. You'd better just call range(1, n+1) which also returns the list [1,2,3,4,5] for n=5:
def fill_list(n):
return range(1, n+1)
Python Examples
pythonexamples.org › python-numpy-array-with-range-of-numbers
Initialize Array with Range of Numbers – NumPy
To initialise an array with a range of numbers in NumPy, you can use numpy.arange() function.
Real Python
realpython.com › how-to-use-numpy-arange
NumPy arange(): How to Use np.arange() – Real Python
March 18, 2026 - In this step-by-step tutorial, you'll learn how to use the NumPy arange() function, which is one of the routines for array creation based on numerical ranges. np.arange() returns arrays with evenly spaced values.
GitHub
gist.github.com › rledford › 0e4fd58b1a7ffc3d9ac6a695e31912fc
Python Array - Fill · GitHub
Python Array - Fill · Raw · fill.py · This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode characters ·
Python Like You Mean It
pythonlikeyoumeanit.com › Module3_IntroducingNumpy › FunctionsForCreatingNumpyArrays.html
Functions for Creating NumPy Arrays — Python Like You Mean It
>>> import numpy as np # creating an array from a Python sequence >>> np.array([i**2 for i in range(5)]) array([ 0, 1, 4, 9, 16]) # creating an array filled with ones >>> np.ones((2, 4)) array([[ 1., 1., 1., 1.], [ 1., 1., 1., 1.]]) # creating an array of evenly-spaced points >>> np.linspace(0, 10, 5) array([ 0.
Moonbooks
en.moonbooks.org › Articles › How-to-Fill-Values-in-an-Array-Between-Two-Index-Arrays-Using-NumPy-
How to Fill Values in an Array Between Two Index Arrays Using NumPy ?
Using broadcasting, we compare the start and end indexes with the column indices (xx) to create a boolean matrix: For a specific row, you can observe the filled ranges:
Reddit
reddit.com › r/learnpython › how to fill a matrix using numpy
r/learnpython on Reddit: How to fill a matrix using numpy
June 18, 2020 -
Hello everyone,
I haven't done any type of linear algebra work with python before, only matlab. In matlab you create a matrix with the proper dimensions, then start filling it up with vectors of the appropriate size. I've tried to look up how to do this in python using a loop, and it doesn't seem as straightforward. It seems you first need to create a list, and append that list. Then convert that list to a numpy array. And then from there it appears you stack them? But stacking seems to only stack 1D and 2D arrays, so it's not exactly what I'm looking for.
For example:
import numpy as np
matrix=np.zeros((rows,columns))
list=[]
for i in range(columns):
for x in range(rows):
list.append(x)
arr=np.array(list)
matrix.append(arr)
list.clear() So in the above case, I've made a list, and converted it into an array with shape (rows, 1). Then I want to add it to the first column of my matrix. Then through the loop, I start to fill my matrix up by filling it one by one with these vectors. However, the issue is I'm trying to add a 1D array, to a multi-D matrix (which numpy doesn't allow you to do).
Hpw do I fill up a matrix using numpy?
Note.nkmk.me
note.nkmk.me › home › python › numpy
NumPy: Create an array with the same value (np.zeros, np.ones, np.full) | note.nkmk.me
January 23, 2024 - To create an array filled with any specified value, use np.full().
H2K Infosys
h2kinfosys.com › home › python tutorials › mastering range of numbers in array with numpy: arange & linspace simplified
Mastering Range of Numbers in Array with Numpy: arange & linspace Simplified
August 13, 2026 - The linspace function in Python, part of the NumPy library, is used to generate an array of evenly spaced numbers over a specified range.
Tudelft
mude.citg.tudelft.nl › workbook-2025 › assignments › PA1.2 › 7_filling_matrix.html
Filling a matrix — MUDE Workbook 2025 - TU Delft
April 13, 2026 - Use a Numpy method to create a 3x3 matrix filled with value 3 on the diagonal and 0 elsewhere. ... Use a Numpy method to create a 10x10 matrix, then assign every other element in the diagonal of the matrix to the value 1 using range and indexing.
GeeksforGeeks
geeksforgeeks.org › python › numpy-ndarray-fill-in-python
numpy.ndarray.fill() in Python - GeeksforGeeks
December 28, 2018 - # Python program explaining # numpy.ndarray.fill() function import numpy as geek a = geek.arange(5) print("a is \n", a) # Using fill() method a.fill(0) print("\nNow a is :\n", a) ... a is [0 1 2 3 4] Now a is : [0 0 0 0 0] Code #3: numpy.ndarray.fill() also works on multidimensional array.
Programming Idioms
programming-idioms.org › idiom › 314 › fill-array-with-value › 7592 › python
Fill array with value, in Python
August 25, 2022 - Fill array with random bytes · Created a zeroed list of integers · Clear a byte array · Cheatsheets · Issues · Report a bug · × · Python · x = [v] * len(x) Python · for index in range(len(x)): x[index] = v · Python · x[:] = [v] * len(x) C++ x.fill(v); C++ fill(begin(x), end(x), ...
Stack Overflow
stackoverflow.com › questions › 49103167 › python-filling-an-array-with-calculated-values
Python - Filling an array with calculated values - Stack Overflow
x = np.linspace(-2, 2, 100) print("\nx values:\n ", x) f2y = np.zeros(len(x)) # print("f2y, empty array of y values: ", f2y) for i in range(0, len(x), 1): for j in x: f2y[i] = f2(j) The f2y array is supposed to fill up with different y-values based on what x value is plugged in.
CloudxLab
cloudxlab.com › assessment › displayslide › 2516 › numpy-arrays-special-types-of-arrays-array-with-values-within-a-particular-range
Numpy - Arrays - Special Types of Arrays - Array with values within a particular range | Automated hands-on| CloudxLab
The above NumPy array my_range_array will be filled with values between 10 and 30 (excluding 30) having a gap of the value of 5 between the consecutive values.
YouTube
youtube.com › codelearn
python fill array with range - YouTube
Download this code from https://codegive.com In Python, the range() function is commonly used to generate a sequence of numbers. You can use this function to...
Published: December 25, 2023
Views: 18