What should you pay attention to when using arrays?

You need to pay attention to the following when using arrays: Out-of-bounds access: Accessing non-existent elements will cause the program to crash. Duplicate elements: The elements in the array are out of order and may be duplicated. Array size is fixed: the size cannot be changed after creation. Null value: An element can store a null value, which represents an unknown or unset value. Traversing an array: You can traverse an array using a for loop or the enumerate function.

Things to note when using arrays

An array is a data structure used to store a collection of elements of the same type. It is one of the most basic data structures, but you need to pay attention to the following when using it:

Out-of-bounds access

Each element of the array has an index, starting from 0 starts. Trying to access a negative number or an element beyond the maximum index will cause the program to crash.

Practical case:

# 创建一个存储整数的数组
array = [1, 2, 3, 4, 5]

# 安全访问元素
print(array[2])  # 输出 3

# 越界访问
try:
    print(array[5])  # IndexError: list index out of range
except IndexError:
    print("越界访问已处理。")

Duplicate elements

The elements in the array are unordered, which means the same element May occur multiple times.

Practical case:

# 创建一个存储布尔值的数组
array = [True, False, True]

# 输出每个元素
for element in array:
    print(element)  # 输出 True、False、True

Fixed array size

Once created, the size of the array is fixed. This means you cannot add or remove elements. If you need to change the size of an array, you must create a new array.

Practical case:

# 创建一个大小为 5 的数组
array = [0] * 5

# 尝试添加一个元素
array.append(6)  # AttributeError: 'list' object has no attribute 'append'

Null value

Array elements can store any type of value, including None . A null value represents an unset or unknown value.

Practical case:

# 创建一个存储字符串的数组
array = ["Hello", "World", None]

# 输出每个元素
for element in array:
    print(element)  # 输出 Hello、World、None

Traverse the array

You can use for loop or # to traverse the array ##enumerate function.

Practical case:

# 使用 for 循环遍历
array = [1, 2, 3, 4, 5]
for element in array:
    print(element)  # 输出 1、2、3、4、5

# 使用 enumerate 函数遍历
array = ["Hello", "World", "Python"]
for index, element in enumerate(array):
    print(f"{index}: {element}")  # 输出 0: Hello、1: World、2: Python

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