How do I fast make a list of 1
When I knew how to write a single line for loop, I could simply my code.
When I review python document and relearn python in detail now, I find range() built-in function it can directly make a list, but I look no one doing this. Why?
2 Answers 2
In Python 2.x
If you want to create a list of numbers from 1 to 100, you simply do:
In Python 3.x
range() no longer returns a list, but instead returns a generator. We can easily convert that into a list though.
When I review python document and relearn python in detail now, I find range() built-in function it can directly make a list, but I look no one doing this.
Depends, if you are using Python 2.X it does but for Python 3.X it produces a range object which should be iterated upon to create a list if you need to.
But in any case for all practical purpose extending a range object as a List comprehension is useless and have an unnecessary memory hogging.
Как создать массив в питоне от 1 до 100
>>> import numpy as np
>>> a = [2, 56, 46, 24, 12]
>>> numbers = np . array (a)
>>> type(numbers)
<class ‘numpy.ndarray’>
>>> numbers
array([ 2, 56, 46, 24, 12])
>>> b = [[5, 6, 10], [25, 64, 17], [14, 25, 14]]
>>> mas = np.array (b)
>>> mas
array([[ 5, 6, 10],
[25, 64, 17],
[14, 25, 14]])
>>> numbers = np.array ([ 1, 5, 47, 78])
>>> numbers
array([ 1, 5, 47, 78])
2. Атрибуты array
2.1. Определение типа элементов array
>>> import numpy as np
>>> numbers_1 = np.array ([[5, 7, 45], [14, 7, 9]])
>>> numbers_1
array([[ 5, 7, 45],
[14, 7, 9]])
>>> numbers_1. dtype
dtype(‘int32’)
>>> numbers_2 = np.array ([[0.5, 0.7, 0.45], [0.14, 0.7, 0.9]])
>>> numbers_2
array([[0.5 , 0.7 , 0.45],
[0.14, 0.7 , 0.9 ]])
>>> numbers_2. dtype
dtype(‘float64’)
2.2. Определение размерности array
>>> import numpy as np
>>> numbers_1 = np.array ([[5, 7, 45], [14, 7, 9]])
>>> numbers_1. ndim
2
>>> numbers_1. shape
(2, 3)
>>> import numpy as np
>>> numbers_1 = np.array ([[5, 7, 45], [14, 7, 9]])
>>> numbers_1. size
6
>>> numbers_1. itemsize
4
2.4. Перебор элементов array
>>> import numpy as np
>>> numbers_1 = np.array ([[5, 7, 45], [14, 7, 9]])
>>> for row in numbers_1:
. for column in row:
. print(column, end=’ ‘)
. print()
.
5 7 45
14 7 9
3. Создание массивов в Python по диапазонам
3.1. Создание диапазонов функцией arange
>>> import numpy as np
>>> np. arange (7)
array([0, 1, 2, 3, 4, 5, 6])
>>> np. arange (5, 10)
array([5, 6, 7, 8, 9])
>>> np. arange (100, 10, -10)
array([100, 90, 80, 70, 60, 50, 40, 30, 20])
3.2. Создание диапазонов чисел с плавающей точкой функцией linspace
>>> import numpy as np
>>> np. linspace (1.0, 2.0, num=5)
array([1. , 1.25, 1.5 , 1.75, 2. ])
>>> np. linspace (1.0, 5.0, num=10)
array([1. , 1.44444444, 1.88888889, 2.33333333, 2.77777778, 3.22222222, 3.66666667, 4.11111111, 4.55555556, 5. ])
3.3. Изменение размерности array методом reshape
>>> import numpy as np
>>> np.arange(1, 37). reshape (6, 6)
array([[ 1, 2, 3, 4, 5, 6],
[ 7, 8, 9, 10, 11, 12],
[13, 14, 15, 16, 17, 18],
[19, 20, 21, 22, 23, 24],
[25, 26, 27, 28, 29, 30],
[31, 32, 33, 34, 35, 36]])
>>> np.arange(1, 37). reshape (4, 9)
array([[ 1, 2, 3, 4, 5, 6, 7, 8, 9],
[10, 11, 12, 13, 14, 15, 16, 17, 18],
[19, 20, 21, 22, 23, 24, 25, 26, 27],
[28, 29, 30, 31, 32, 33, 34, 35, 36]])
3.4. Заполнение array конкретными значениями. Функции zeros , ones , full
>>> import numpy as np
>>> np. zeros (7)
array([0., 0., 0., 0., 0., 0., 0.])
>>> np. zeros ((3, 3))
array([[0., 0., 0.],
[0., 0., 0.],
[0., 0., 0.]])
>>> import numpy as np
>>> np. ones ((3, 3))
array([[1., 1., 1.],
[1., 1., 1.],
[1., 1., 1.]])
>>> import numpy as np
>>> np. ones ((3, 3), dtype=int )
array([[1, 1, 1],
[1, 1, 1],
[1, 1, 1]])
>>> np. zeros ((3, 3), dtype=int )
array([[0, 0, 0],
[0, 0, 0],
[0, 0, 0]])
>>> import numpy as np
>>> np. full ((3, 4), 55)
array([[55, 55, 55, 55],
[55, 55, 55, 55],
[55, 55, 55, 55]])
>>> np. full ((2, 4), 21.2)
array([[21.2, 21.2, 21.2, 21.2],
[21.2, 21.2, 21.2, 21.2]])
Create a List from 1 to 100 in Python
In this article, we will see how to create a list from 1 to 100 in Python.
Ways to create a list from 1 to 100 in Python
A list is an object that contains a sequence of elements in Python.
We will discuss how to create a list from 1 to 100 in Python.
Using the range() function to create a list from 1 to 100 in Python
In Python, we can use the range() function to create an iterator sequence between two endpoints. We can use this function to create a list from 1 to 100 in Python.
The function accepts three parameters start , stop , and step . The start parameter mentions the starting number of the iterator and the ending point is specified in the stop parameter. We use the step parameter to specify the step increment between two consecutive numbers. By default, the step parameter has a value of 1.
Since the range() function returns an iterator, we need to convert it to a list. For this, we will use the list() constructor.
See the code below.
In the above example, we do not mention the step parameter. Note that we have to specify the value for the ending point as 101. This is because the last value is not included in the sequence.
The range() function works a little differently for users working with Python 2. In this version, the final result is already returned in a list so we do not need to perform any explicit conversion.
Using the numpy.arange() function to create a list from 1 to 100 in Python
The numpy.arange() function is similar to the previous method. It also takes three parameters start , stop , and step , and returns a sequence of numbers based on the value of these parameters.
However, the final result in this function is returned in a numpy array. So we need to convert this array to a list which can be done by using the tolist() function. This function is used to return the elements of an array in a list.
How to create an array of numbers 1 to n in python
An array is a collection of items of same type stored at contiguous memory locations. To access the elements, you only need to know the memory address of the first item of an array which is also known as base address. You can access all other items or traverse in an array by simply adding an offset to this base address. Python lists can also be treated as arrays but the lists can store multiple data items of different datatypes. This article is about how to create an array of numbers 1 to N in Python. If you want to learn more about Python Programming, Visit Python Programming Tutorials.
- CREATION OF AN ARRAY OF NUMBERS 1 TO N USING A RANGE() FUNCTION IN PYTHON.
- CREATE AN ARRAY USING THE USER-DEFINED FUNCTION
- CREATING AN ARRAY USING A NUMPY-ARANGE() FUNCTION
- CREATE AN ARRAY USING PYTHON MODULE ARRAY
In the first three methods, we’ll see how lists can be treated as arrays. Python has a module called array which is used to work only with specific data values. The last method discusses how to create an array using this module. Lets discuss all these methods in detail.
CREATING AN ARRAY USING THE RANGE() FUNCTION
As discussed previously, python lists can be treated as arrays. To create an array of a certain range we can use the range() function as it specifies the range of the list and then typecast the range() by using the list command as shown in the code below. We can set the range of the list from 1 to N and N should be any integer number.
CODE:
creating an array by a user-defined function
Another way is to create a function and pass the length of an array as a parameter to this function. In the example below, we have created a function by the name of List-Function. The function takes parameter ‘n’ which represents the length of the array. In this function, a for loop is used which treats n as the last index of the array and append the number in the List_array starting from 0 up to the maximum length ‘n’ as shown below.
CODE:
cREATING AN ARRAY USING nUMPY.ARANGE() FUNCTION
The numpy library provides an arrange() function which takes two parameters as an integers and generate the numbers starting from the first parameter upto the last parameter. Typecast the arange() function using the list command and an array is created.
numpy.arange() is used to create an array of large sizes.
CREATE AN ARRAY USING PYTHON MODULE ARRAY
An array module of python is used to create an array consisting of elements or items of same datatypes. The array module takes two arguments as an input. The first one is datatype of an array such as ‘i’ for integer. All other datatypes are given in the this link. The second argument consists of the elements or items of an array.
In the example above, we have created two arrays arr1 and arr2 of integers and floating numbers. The function display here is used to print the contents of an array created. It takes two arguments: an array ‘n’ and the size of array ‘s’ created.