Python中的数组|第二套（重要功能）

Python中的数组|第一组（介绍及功能）

下面是更多功能。

1. typecode :- 该函数返回初始化数组的数据类型。

2. itemsize :- 此函数返回单个数组元素的大小（以字节为单位）。

3. buffer_info() :- 返回一个元组，表示存储数组的地址和其中元素的数量。

# Python code to demonstrate the working of 
# typecode, itemsize, buffer_info()
   
# 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, 2, 5]) 
  
# using typecode to print datatype of array
print ("The datatype of array is : ")
print (arr.typecode)
  
# using itemsize to print itemsize of array
print ("The itemsize of array is : ")
print (arr.itemsize)
  
# using buffer_info() to print buffer info. of array
print ("The buffer info. of array is : ")
print (arr.buffer_info())

输出：

The datatype of array is : 
i
The itemsize of array is : 
4
The buffer info. of array is : 
(29784224, 6)

除了导入数组，我们还可以使用 * 来导入数组。

# importing "array" using * for array operations
from array import *
   
# initializing array with array values
# initializes array with signed integers
arr = array('i',[1, 2, 3, 1, 2, 5]) 
  
print(arr)

输出：

array('i', [1, 2, 3, 1, 2, 5])

4. count() :- 这个函数计算数组中提到的参数的出现次数。

5. extend(arr) :- 该函数将其参数中提到的整个数组附加到指定的数组。

# Python code to demonstrate the working of 
# count() and extend()
   
# importing "array" for array operations
import array
   
# initializing array 1 with array values
# initializes array with signed integers
arr1 = array.array('i',[1, 2, 3, 1, 2, 5]) 
  
# initializing array 2 with array values
# initializes array with signed integers
arr2 = array.array('i',[1, 2, 3]) 
  
# using count() to count occurrences of 1 in array
print ("The occurrences of 1 in array is : ")
print (arr1.count(1))
  
# using extend() to add array 2 elements to array 1 
arr1.extend(arr2)
  
print ("The modified array is : ")
for i in range (0,9):
    print (arr1[i])

输出：

The occurrences of 1 in array is : 
2
The modified array is : 
1
2
3
1
2
5
1
2
3

6. fromlist(list) :- 此函数用于将其参数中提到的列表附加到数组末尾。

7. tolist() :- 此函数用于将数组转换为列表。

# Python code to demonstrate the working of 
# fromlist() and tolist()
   
# 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, 2, 5]) 
  
# initializing list
li = [1, 2, 3]
  
# using fromlist() to append list at end of array
arr.fromlist(li)
  
# printing the modified array
print ("The modified array is : ",end="")
for i in range (0,9):
    print (arr[i],end=" ")
  
# using tolist() to convert array into list
li2 = arr.tolist()
  
print ("\r")
  
# printing the new list
print ("The new list created is : ",end="")
for i in range (0,len(li2)):
    print (li2[i],end=" ")

输出：

The modified array is : 1 2 3 1 2 5 1 2 3 
The new list created is : 1 2 3 1 2 5 1 2 3