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  • 本文实例讲述了python数组复制拷贝的实现方法。分享给大家供大家参考。具体分析如下: python中直接通过等号赋值实际上只是引用地址的传递 如: a = [1,2,3,4,5] b=a 当a的值改变时,b的值也会随之改变 如果希望b...
  • 比如想过滤掉字符串数组中某个敏感词,示范代码如下: #filter out some unwanted tags def passed(item): try: return item != "techbrood" #can be more a complicated condition here except ValueError: return...
  • 主要介绍了python数组过滤实现方法,涉及Python针对数组的相关操作技巧,具有一定参考借鉴价值,需要的朋友可以参考下
  • 今天小编就为大家分享一篇对Python 数组的切片操作详解,具有很好的参考价值,希望对大家有所帮助。一起跟随小编过来看看吧
  • 本文主要介绍python数组循环语法。主要方式有元素遍历,索引遍历,enumerate, zip, list内部等。 普通循环 list1 = ['item1', 'item2', 'item3'] for item in list1: print(item) //结果 item1 item2 item3 根据...
  • python数组_Python数组

    千次阅读 2020-07-14 13:54:52
    python数组Python Array contains a sequence of data. In python programming, there is no exclusive array object because we can perform all the array operations using list. Today we will learn about ...

    python数组

    Python Array contains a sequence of data. In python programming, there is no exclusive array object because we can perform all the array operations using list. Today we will learn about python array and different operations we can perform on an array (list) in python. I will assume that you have the basic idea of python variables and python data types.

    Python Array包含一系列数据。 在python编程中,没有排他的数组对象,因为我们可以使用list执行所有数组操作。 今天,我们将学习python数组以及可以在python中的数组(列表)上执行的不同操作。 我将假定您具有python变量和python数据类型的基本概念。

    Python数组 (Python Array)

    Python supports all the array related operations through its list object. Let’s start with one-dimensional array initialization.

    Python通过其list对象支持所有与数组相关的操作。 让我们从一维数组初始化开始。

    Python数组示例 (Python array example)

    Python array elements are defined within the brace [] and they are comma separated. The following is an example of declaring python one-dimensional array.

    Python数组元素在大括号[]中定义,并且用逗号分隔。 以下是声明python一维数组的示例。

    arr = [ 1, 2 ,3, 4, 5]
    print (arr)
    print (arr[2])
    print (arr[4])

    Output of above one dimensional array example program will be:

    上面的一维数组示例程序的输出将是:

    [1, 2, 3, 4, 5]
    3
    5

    Array indexing starts from 0. So the value of index 2 of variable arr is 3.

    数组索引从0开始。因此变量arr的索引2的值为3。

    In some other programming languages such as Java, when we define an array we also need to define element type, so we are limited to store only that type of data in the array. For example, int brr[5]; is able to store integer data only.

    在Java等其他编程语言中,当我们定义数组时,我们还需要定义元素类型,因此我们只能在数组中存储该类型的数据。 例如, int brr[5]; 只能存储整数数据。

    But python gives us the flexibility to have the different type of data in the same array. It’s cool, right? Let’s see an example.

    但是python使我们可以灵活地在同一数组中拥有不同类型的数据。 很酷吧? 让我们来看一个例子。

    student_marks = ['Akkas' , 45, 36.5]
    marks = student_marks[1]+student_marks[2]
    print(student_marks[0] + ' has got in total = %d + %f = %f ' % (student_marks[1], student_marks[2], marks ))

    It give the following output:

    它给出以下输出:

    Akkas has got in total = 45 + 36.500000 = 81.500000 marks

    In the above example you can see that, student_marks array have three type of data – string, int and float.

    在上面的示例中,您可以看到, student_marks数组具有三种类型的数据-字符串,整数和浮点数。

    Python多维数组 (Python multidimensional array)

    Two dimensional array in python can be declared as follows.

    python中的二维数组可以声明如下。

    arr2d = [ [1,3,5] ,[2,4,6] ]
    print(arr2d[0]) # prints elements of row 0
    print(arr2d[1]) # prints elements of row 1
    print(arr2d[1][1]) # prints element of row = 1, column = 1

    It will produce the following output:

    它将产生以下输出:

    [1, 3, 5]                                                                                                                                                                       
    [2, 4, 6]                                                                                                                                                                       
    4

    Similarly, we can define a three-dimensional array or multidimensional array in python.

    同样,我们可以在python中定义三维数组或多维数组。

    Python阵列范例 (Python array examples)

    Now that we know how to define and initialize an array in python. We will look into different operations we can perform on a python array.

    现在,我们知道了如何在python中定义和初始化数组。 我们将研究可以在python数组上执行的不同操作。

    使用for循环遍历Python数组 (Python array traversing using for loop)

    We can use for loop to traverse through elements of an array. Below is a simple example of for loop to traverse through an array.

    我们可以使用for循环遍历数组的元素。 以下是for循环遍历数组的简单示例。

    arrayElement = ["One", 2, 'Three' ]
    for i in range(len(arrayElement)):
       print(arrayElement[i])

    Below image shows the output produced by the above array example program.

    下图显示了上述数组示例程序产生的输出。

    使用for循环遍历2D数组 (Traversing 2D-array using for loop)

    The following code print the elements row-wise then the next part prints each element of the given array.

    下面的代码按行打印元素,然后下一部分打印给定数组的每个元素。

    arrayElement2D = [ ["Four", 5, 'Six' ] , [ 'Good',  'Food' , 'Wood'] ]
    for i in range(len(arrayElement2D)):
       print(arrayElement2D[i])
    
    for i in range(len(arrayElement2D)):
       for j in range(len(arrayElement2D[i])):
           print(arrayElement2D[i][j])

    This will output:

    python array example for loop traversing 2d array

    这将输出:

    Python数组追加 (Python array append)

    arrayElement = ["One", 2, 'Three' ]
    arrayElement.append('Four')
    arrayElement.append('Five')
    for i in range(len(arrayElement)):
       print(arrayElement[i])

    The new element Four and Five will be appended at the end of the array.

    新元素“四”和“五”将添加到数组的末尾。

    One
    2
    Three
    Four
    Five

    You can also append an array to another array. The following code shows how you can do this.

    您也可以将一个数组附加到另​​一个数组。 以下代码显示了如何执行此操作。

    arrayElement = ["One", 2, 'Three' ]
    newArray = [ 'Four' , 'Five']
    arrayElement.append(newArray);
    print(arrayElement)
    ['One', 2, 'Three', ['Four', 'Five']]

    Now our one-dimensional array arrayElement turns into a multidimensional array.

    现在,我们的一维数组arrayElement变成了多维数组。

    Python数组大小 (Python array size)

    We can use len function to determine the size of an array. Let’s look at a simple example for python array length.

    我们可以使用len函数来确定数组的大小。 让我们看一个简单的python数组长度示例。

    arr = ["One", 2, 'Three' ]
    
    arr2d = [[1,2],[1,2,3,4]]
    
    print(len(arr))
    print(len(arr2d))
    print(len(arr2d[0]))
    print(len(arr2d[1]))

    Python数组切片 (Python array slice)

    Python provides a special way to create an array from another array using slice notation. Let’s look at some python array slice examples.

    Python提供了一种特殊的方式来使用切片符号从另一个数组创建一个数组。 让我们看一些python数组切片示例。

    arr = [1,2,3,4,5,6,7]
    
    #python array slice
    
    arr1 = arr[0:3] #start to index 2
    print(arr1)
    
    arr1 = arr[2:] #index 2 to end of arr
    print(arr1)
    
    arr1 = arr[:3] #start to index 2
    print(arr1)
    
    arr1 = arr[:] #copy of whole arr
    print(arr1)
    
    arr1 = arr[1:6:2] # from index 1 to index 5 with step 2
    print(arr1)

    Below image shows the python array slice example program output.

    下图显示了python array slice示例程序输出。

    Python数组插入 (Python array insert)

    We can insert an element in the array using insert() function.

    我们可以使用insert()函数在数组中插入一个元素。

    arr = [1,2,3,4,5,6,7]
    
    arr.insert(3,10)
    
    print(arr)

    Python数组弹出 (Python array pop)

    We can call the pop function on the array to remove an element from the array at the specified index.

    我们可以在数组上调用pop函数,以指定索引从数组中删除元素。

    arr = [1,2,3,4,5,6,7]
    
    arr.insert(3,10)
    print(arr)
    
    arr.pop(3)
    print(arr)

    That’s all about python array and different operations we can perform for the arrays in python.

    这就是关于python数组以及我们可以在python中为数组执行的不同操作的全部内容。

    翻译自: https://www.journaldev.com/14971/python-array

    python数组

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  • Python数组定义方法

    2020-09-21 16:47:45
    主要介绍了Python数组定义方法,结合实例形式分析了Python一维数组与二维数组的定义方法与相关注意事项,需要的朋友可以参考下
  • python 数组添加数组_Python添加到数组

    万次阅读 2020-07-18 00:14:52
    python 数组添加数组Python doesn’t have any specific data type as an array. We can use List that has all the characteristics of an array. Python没有任何特定的数据类型作为数组。 我们可以使用具有数组...

    python 数组添加数组

    Python doesn’t have any specific data type as an array. We can use List that has all the characteristics of an array.

    Python没有任何特定的数据类型作为数组。 我们可以使用具有数组所有特征的List。

    Python array module can be used to create an array of integers and floating-point numbers.

    Python数组模块可用于创建整数和浮点数的数组。

    If you want to do some mathematical operations on an array, you should use the NumPy module.

    如果要对数组进行一些数学运算,则应使用NumPy模块。

    1. Python添加到数组 (1. Python add to Array)

    • If you are using List as an array, you can use its append(), insert(), and extend() functions. You can read more about it at Python add to List.

      如果将List用作数组,则可以使用其append(),insert()和extend()函数。 您可以在Python add to List中阅读有关它的更多信息。
    • If you are using array module, you can use the concatenation using the + operator, append(), insert(), and extend() functions to add elements to the array.

      如果使用的是数组模块,则可以使用+运算符,append(),insert()和extend()函数进行串联,以将元素添加到数组中。
    • If you are using NumPy arrays, use the append() and insert() function.

      如果您使用的是NumPy数组,请使用append()和insert()函数。

    2.使用数组模块将元素添加到数组 (2. Adding elements to an Array using array module)

    • Using + operator: a new array is returned with the elements from both the arrays.

      使用+运算符:返回一个新数组,其中包含两个数组中的元素。
    • append(): adds the element to the end of the array.

      append():将元素添加到数组的末尾。
    • insert(): inserts the element before the given index of the array.

      insert():将元素插入到数组的给定索引之前。
    • extend(): used to append the given array elements to this array.

      extend():用于将给定的数组元素附加到此数组。
    import array
    
    arr1 = array.array('i', [1, 2, 3])
    arr2 = array.array('i', [4, 5, 6])
    
    print(arr1)  # array('i', [1, 2, 3])
    print(arr2)  # array('i', [4, 5, 6])
    
    arr3 = arr1 + arr2
    print(arr3)  # array('i', [1, 2, 3, 4, 5, 6])
    
    arr1.append(4)
    print(arr1)  # array('i', [1, 2, 3, 4])
    
    arr1.insert(0, 10)
    print(arr1)  # array('i', [10, 1, 2, 3, 4])
    
    arr1.extend(arr2)
    print(arr1)  # array('i', [10, 1, 2, 3, 4, 4, 5, 6])

    3.向NumPy数组添加元素 (3. Adding elements to the NumPy Array)

    • append(): the given values are added to the end of the array. If the axis is not provided, then the arrays are flattened before appending.

      append():将给定值添加到数组的末尾。 如果未提供轴,则在附加之前将阵列弄平。
    • insert(): used to insert values at the given index. We can insert elements based on the axis, otherwise, the elements will be flattened before the insert operation.

      insert():用于在给定索引处插入值。 我们可以基于轴插入元素,否则,将在插入操作之前将元素展平。
    >>> import numpy as np
    >>> np_arr1 = np.array([[1, 2], [3, 4]])
    >>> np_arr2 = np.array([[10, 20], [30, 40]])
    >>> 
    >>> np.append(np_arr1, np_arr2)
    array([ 1,  2,  3,  4, 10, 20, 30, 40])
    >>>
    >>> np.append(np_arr1, np_arr2, axis=0)
    array([[ 1,  2],
           [ 3,  4],
           [10, 20],
           [30, 40]])
    >>>
    >>> np.append(np_arr1, np_arr2, axis=1)
    array([[ 1,  2, 10, 20],
           [ 3,  4, 30, 40]])
    >>> 
    >>> np.insert(np_arr1, 1, np_arr2, axis=0)
    array([[ 1,  2],
           [10, 20],
           [30, 40],
           [ 3,  4]])
    >>> 
    >>> np.insert(np_arr1, 1, np_arr2, axis=1)
    array([[ 1, 10, 30,  2],
           [ 3, 20, 40,  4]])
    >>>

    4.参考 (4. References)

    翻译自: https://www.journaldev.com/33185/python-add-to-array

    python 数组添加数组

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  • 今天小编就为大家分享一篇Python 实现数组相减示例,具有很好的参考价值,希望对大家有所帮助。一起跟随小编过来看看吧
  • 基本的Python模块,将Javascript数组的属性和方法带入Python。 用法 用法示例: from jsarray import JSArray array = JSArray ( range ( 10 )) ( array . map ( lambda item : item ** 2 ) . filter ( lambda ...
  • python数组查找元素LCM is the lowest multiple of two or more numbers. Multiples of a number are those numbers which when divided by the number leave no remainder. When we are talking about the multiple...

    python数组查找元素

    LCM is the lowest multiple of two or more numbers. Multiples of a number are those numbers which when divided by the number leave no remainder. When we are talking about the multiple, we consider only the positive number. For example, the LCM of 12 and 48 is 48 because 48 is 4th multiple of 12 and 48 is 1st multiple of 48. Here, an array of positive elements will be provided by the user and we have to find the LCM of the elements of the array by using the Python. To find LCM of the elements of the array, use the following algo,

    LCM两个或多个数字最小倍数 。 数字的倍数是那些除以数字后没有余数的数字。 当我们谈论倍数时,我们只考虑正数。 例如,12和48的LCM是48,因为48是4 12 倍数和4848 1 倍数。 在这里,用户将提供一个正元素数组,我们必须使用Python查找该数组元素的LCM 。 要查找数组元素的LCM ,请使用以下算法,

    Algorithm to find the LCM of array elements

    查找数组元素的LCM的算法

    • We need to import the math module to find the GCD of two numbers using math.gcd() function.

      我们需要导入math模块以使用math.gcd()函数查找两个数字的GCD。

    • At first, find the LCM of initial two numbers using: LCM(a,b) = a*b/GCD(a,b). And, then find the LCM of three numbers with the help of LCM of first two numbers using LCM(ab,c) = lcm(lcm(a1, a2), a3). The same concept we have implemented.

      首先,使用以下公式找到初始两个数字的LCM: LCM(a,b)= a * b / GCD(a,b) 。 然后,使用LCM(ab,c)= lcm(lcm(a1,a2),a3)在前两个数字的LCM的帮助下找到三个数字的LCM。 我们已经实现了相同的概念。

    Now, we will write the Python program in a simple way by implementing the above algorithm.

    现在,我们将通过实现上述算法以简单的方式编写Python程序。

    Program:

    程序:

    # importing the module
    import math
    
    # function to calculate LCM
    def LCMofArray(a):
      lcm = a[0]
      for i in range(1,len(a)):
        lcm = lcm*a[i]//math.gcd(lcm, a[i])
      return lcm
    
    
    # array of integers
    arr1 = [1,2,3]
    arr2 = [2,3,4]
    arr3 = [3,4,5]
    arr4 = [2,4,6,8]
    arr5 = [8,4,12,40,26,28]
    
    print("LCM of arr1 elements:", LCMofArray(arr1))
    print("LCM of arr2 elements:", LCMofArray(arr2))
    print("LCM of arr3 elements:", LCMofArray(arr3))
    print("LCM of arr4 elements:", LCMofArray(arr4))
    print("LCM of arr5 elements:", LCMofArray(arr5))
    
    

    Output

    输出量

    LCM of arr1 elements: 6
    LCM of arr2 elements: 12
    LCM of arr3 elements: 60
    LCM of arr4 elements: 24
    LCM of arr5 elements: 10920
    
    
    

    翻译自: https://www.includehelp.com/python/find-the-lcm-of-the-array-elements.aspx

    python数组查找元素

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  • python数组查找元素Given an integer array and we have to find the sum of all elements in Python. 给定一个整数数组,我们必须找到Python中所有元素的总和 。 查找数组元素的总和 (Finding the sum of array ...

    python数组查找元素

    Given an integer array and we have to find the sum of all elements in Python.

    给定一个整数数组,我们必须找到Python中所有元素的总和

    查找数组元素的总和 (Finding the sum of array elements)

    There are two ways to find the sum of all array elements, 1) traverse/access each element and add the elements in a variable sum, and finally, print the sum. And, 2) find the sum of array elements using sum() function.

    有两种查找所有数组元素之和的方法: 1)遍历/访问每个元素并将元素添加到变量sum中 ,最后打印出sum 。 并且2)使用sum()函数找到数组元素的总和

    Example:

    例:

        Input: 
        arr = [10, 20, 30, 40, 50]
        Output:
        sum = 150
    
    

    用于数组元素求和的Python程序 (Python program for sum of the array elements)

    # Python program for sum of the array elements
    
    # functions to find sum of elements
    
    # Approach 1
    def sum_1(arr):
        result = 0
        for x in arr:
            result += x
        return result
    
    # Approach 2
    def sum_2(arr):
        result = sum(arr)
        return result
    
    # main function
    if __name__ == "__main__":
        arr = [10, 20, 30, 40, 50]
        print ('sum_1: {}'.format(sum_1(arr)))
        print ('sum_2: {}'.format(sum_2(arr)))
    
    

    Output

    输出量

    sum_1: 150
    sum_2: 150
    
    
    

    翻译自: https://www.includehelp.com/python/find-the-sum-of-all-elements-of-an-array.aspx

    python数组查找元素

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  • python 数组比较

    千次阅读 2019-11-28 09:22:48
    python可以直接使用==进行数组之间的比较,比较的结果是和数组一样大小的bool数组。即下标相对应位置上的值相同时,为True;否则,为False。 两数组==的返回结果: any()、all() 上面提到了数组之间利用==进行比较...
  • Python数组属性方法

    2020-08-26 18:49:33
    数组属性的使用:* 数组对象提供了相应的属性,以读取所需要的属性值 (1)、ndim属性,返回数组的维数 import numpy as np ar1 = np.array([[i for i in "abc"],[i for i in "def"],[i for i in "ghi"]]) #建立一...
  • 下面小编就为大家分享一篇python 显示数组全部元素的方法,具有很好的参考价值,希望对大家有所帮助。一起跟随小编过来看看吧
  • Python 对数组等对象拷贝默认采用的方法是引用传递,即地址传递,修改拷贝的值的时候原对象也会随之改变。 如: origin = np.array([1,1,2,2,3,3,4,5]) filter_arr = [1,2,3] for i in range(3): temp = origin ...
  • python数组反转Tuples in Python are a collection of elements in a round bracket() or not but separated by commas. Tuples are similar to list in some operations like indexing, concatenation, etc. but ...
  • 最近遇到一个数组和向量相关的坑,网上搜了个遍,发现都没有说明白的。记录一下。 1、在做机器学习时,发现有些函数需要向量,这时候需要把数组转化为向量。...一、python中如何表示向量和数组的? ...
  • 今天小编就为大家分享一篇python数组n等分的实例,具有很好的参考价值,希望对大家有所帮助。一起跟随小编过来看看吧
  • python数组的反转

    千次阅读 2019-09-04 15:23:29
    import numpy as np arr = np.arange(10) # 反转前 print(arr) 输出结果: [0 1 2 3 4 5 6 7 8 9] # 反转后 arr2 = arr[::-1] print(arr2) 输出结果: [9 8 7 6 5 4 3 2 1 0]
  • python数组截取

    万次阅读 2019-04-21 00:10:26
    import tensorflow as tf import numpy as np # one-dimention a = np.array([0,1,2,3,4,5,6,7,8,9]) print(a) b=a[:4] print(b) c=a[4:] print(c) # multi-dimention d = np.array([[0,1,2,3,4,5,6,7,8,9],[1,2,3,4...
  • Python 数组操作

    万次阅读 2018-11-14 21:35:13
    以身为棋,胜天半子 整理以前写的代码,复习一下基础知识 li = [] for i in range(20): if (i % 2) == 0: li.append(i) ...很简单的数组遍历添加,for循环加if判断筛选出20以内的偶数 li = [1] ...
  • python数组的行列操作

    千次阅读 2020-07-16 16:28:46
    # -*- coding: utf-8 -*- import numpy as np listdata = [[1,1,2], [1,2,2], ...print("原数组:") print(newlistdata) print() print("取第一行:", newlistdata[0]) print("取第二行:", newlis
  • python数组求和与平均值

    万次阅读 2020-04-04 09:46:43
    python数组求和与平均值 ls=[4,9,19,8,391,39,9,283,45] sum(ls) average=sum(ls)/len(ls) print('累加值',sum(ls),'平均值',average)
  • 有关python数组下标

    千次阅读 2019-10-02 15:17:32
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    2020-03-16 14:47:55
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