Python数组Array用法经典指南 _Python开发

目录数组是存储在连续内存位置的项目的集合。想法是将相同类型的多个项目存储在一起。通过简单地将偏移量添加到基本值(即数组的第一个元素的存储位置(通常由数组的名称表示)), 可以更轻松地计算每个元素的位置。
为简单起见, 我们可以考虑一系列楼梯, 在每个楼梯上都放置一个值(假设你的一个朋友)。在这里, 你只需知道朋友走过的步数即可确定他们的位置。数组可以在Python中由名为的模块处理
Array
。当我们只需要操作特定的数据类型值时, 它们就很有用。用户可以治疗
列表
作为数组。但是, 用户不能限制列表中存储的元素的类型。如果你使用
Array
模块, 数组的所有元素必须是同一类型。

文章图片
创建一个数组 Python中的数组可以通过导入来创建Array模块。数组(数据类型, value_list)用于创建具有在其参数中指定的数据类型和值列表的数组。

# Python program to demonstrate # Creation of Array # importing "array" for array creations import array as arr# creating an array with integer type a = arr.array( 'i' , [ 1 , 2 , 3 ])# printing original array print ( "The new created array is : " , end = " " ) for i in range ( 0 , 3 ): print (a[i], end = " " ) print ()# creating an array with float type b = arr.array( 'd' , [ 2.5 , 3.2 , 3.3 ])# printing original array print ( "The new created array is : " , end = " " ) for i in range ( 0 , 3 ): print (b[i], end = " " )

输出：

The new created array is :1 2 3 The new created array is :2.5 3.2 3.3

下面提到一些数据类型, 这将有助于创建不同数据类型的数组。

文章图片
将元素添加到数组可以使用内置元素将元素添加到数组插入()功能。插入用于将一个或多个数据元素插入数组。根据要求, 可以在数组的开始, 结尾或任何给定的索引处添加新元素。附加()还用于在数组末尾添加其参数中提到的值。

# Python program to demonstrate # Adding Elements to a Array# importing "array" for array creations import array as arr# array with int type a = arr.array( 'i' , [ 1 , 2 , 3 ])print ( "Array before insertion : " , end = " " ) for i in range ( 0 , 3 ): print (a[i], end = " " ) print ()# inserting array using # insert() function a.insert( 1 , 4 )print ( "Array after insertion : " , end = " " ) for i in (a): print (i, end = " " ) print () # array with float type b = arr.array( 'd' , [ 2.5 , 3.2 , 3.3 ])print ( "Array before insertion : " , end = " " ) for i in range ( 0 , 3 ): print (b[i], end = " " ) print ()# adding an element using append() b.append( 4.4 )print ( "Array after insertion : " , end = " " ) for i in (b): print (i, end = " " ) print ()

输出：

Array before insertion : 1 2 3 Array after insertion :1 4 2 3 Array before insertion : 2.5 3.2 3.3 Array after insertion :2.5 3.2 3.3 4.4

从数组访问元素 【Python数组Array用法经典指南】为了访问数组项, 请参考索引号。使用索引运算符[]访问数组中的项目。索引必须是整数。

# Python program to demonstrate # accessing of element from list# importing array module import array as arr# array with int type a = arr.array( 'i' , [ 1 , 2 , 3 , 4 , 5 , 6 ])# accessing element of array print ( "Access element is: " , a[ 0 ])# accessing element of array print ( "Access element is: " , a[ 3 ])# array with float type b = arr.array( 'd' , [ 2.5 , 3.2 , 3.3 ])# accessing element of array print ( "Access element is: " , b[ 1 ])# accessing element of array print ( "Access element is: " , b[ 2 ])

输出：

Access element is:1 Access element is:4 Access element is:3.2 Access element is:3.3

从阵列中删除元素可以使用内置从数组中删除元素去掉()函数, 但如果集合中不存在元素, 则会发生错误。去掉()方法一次只删除一个元素, 要删除元素范围, 则使用迭代器。pop()函数也可以用于从数组中删除并返回一个元素, 但是默认情况下, 它仅删除数组中的最后一个元素, 以从数组的特定位置删除元素, 该元素的索引作为参数传递给pop()方法。
注意 -List中的Remove方法将仅删除搜索到的元素的第一个匹配项。

# Python program to demonstrate # Removal of elements in a Array# importing "array" for array operations import array# initializing array with array values # initializes array with signed integers arr = array.array( 'i' , [ 1 , 2 , 3 , 1 , 5 ]) # printing original array print ( "The new created array is : " , end = "") for i in range ( 0 , 5 ): print (arr[i], end = " " )print ( "\r" )# using pop() to remove element at 2nd position print ( "The popped element is : " , end = "") print (arr.pop( 2 ))# printing array after popping print ( "The array after popping is : " , end = "") for i in range ( 0 , 4 ): print (arr[i], end = " " )print ( "\r" )# using remove() to remove 1st occurrence of 1 arr.remove( 1 )# printing array after removing print ( "The array after removing is : " , end = "") for i in range ( 0 , 3 ): print (arr[i], end = " " )

输出如下：

The new created array is : 1 2 3 1 5 The popped element is : 3 The array after popping is : 1 2 1 5 The array after removing is : 2 1 5

数组切片在Python数组中, 有多种方法可以打印包含所有元素的整个数组, 但是要从数组中打印特定范围的元素, 我们使用
切片操作
。使用冒号(:)对数组执行切片操作。要从开始到范围内打印元素, 请使用[：Index], 要从最终位置使用[：-Index]打印元素, 要从特定索引开始打印直到最后, 使用[Index：], 要打印范围内的元素, 请使用[开始索引：结束索引], 并使用切片操作打印整个列表, 请使用[：]。此外, 要以相反的顺序打印整个数组, 请使用[::-1]。

文章图片

# Python program to demonstrate # silicing of elements in a Array# importing array module import array as arr# creating a list l = [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ]a = arr.array( 'i' , l) print ( "Intial Array: " ) for i in (a): print (i, end = " " )# Print elements of a range # using Slice operation Sliced_array = a[ 3 : 8 ] print ( "\nSlicing elements in a range 3-8: " ) print (Sliced_array)# Print elements from a # pre-defined point to end Sliced_array = a[ 5 :] print ( "\nElements sliced from 5th " "element till the end: " ) print (Sliced_array)# Printing elements from # beginning till end Sliced_array = a[:] print ( "\nPrinting all elements using slice operation: " ) print (Sliced_array)

输出：

Intial Array: 1 2 3 4 5 6 7 8 9 10 Slicing elements in a range 3-8: array('i', [4, 5, 6, 7, 8])Elements sliced from 5th element till the end: array('i', [6, 7, 8, 9, 10])Printing all elements using slice operation: array('i', [1, 2, 3, 4, 5, 6, 7, 8, 9, 10])

在数组中搜索元素为了搜索数组中的元素, 我们使用内置的python指数()方法。此函数返回参数中提到的第一次出现的值的索引。

# Python code to demonstrate # searching an element in array# importing array module import array# initializing array with array values # initializes array with signed integers arr = array.array( 'i' , [ 1 , 2 , 3 , 1 , 2 , 5 ]) # printing original array print ( "The new created array is : " , end = "") for i in range ( 0 , 6 ): print (arr[i], end = " " )print ( "\r" )# using index() to print index of 1st occurrenece of 2 print ( "The index of 1st occurrence of 2 is : " , end = "") print (arr.index( 2 ))# using index() to print index of 1st occurrenece of 1 print ( "The index of 1st occurrence of 1 is : " , end = "") print (arr.index( 1 ))

输出如下：

The new created array is : 1 2 3 1 2 5 The index of 1st occurrence of 2 is : 1 The index of 1st occurrence of 1 is : 0

更新数组中的元素为了更新数组中的元素, 我们只需将新值重新分配给想要更新的所需索引即可。

# Python code to demonstrate # how to update an element in array# importing array module import array# initializing array with array values # initializes array with signed integers arr = array.array( 'i' , [ 1 , 2 , 3 , 1 , 2 , 5 ]) # printing original array print ( "Array before updation : " , end = "") for i in range ( 0 , 6 ): print (arr[i], end = " " )print ( "\r" )# updating a element in a array arr[ 2 ] = 6 print ( "Array after updation : " , end = "") for i in range ( 0 , 6 ): print (arr[i], end = " " ) print ()# updating a element in a array arr[ 4 ] = 8 print ( "Array after updation : " , end = "") for i in range ( 0 , 6 ): print (arr[i], end = " " )

输出如下：