You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
hello-algo/codes/python/chapter_array_and_linkedlist/array.py

91 lines
2.4 KiB

'''
File: array.py
Created Time: 2022-11-25
Author: Krahets (krahets@163.com)
'''
import sys, os.path as osp
sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
from include import *
""" 随机访问元素 """
def randomAccess(nums):
# 在区间 [0, len(nums)) 中随机抽取一个数字
random_index = random.randint(0, len(nums))
# 获取并返回随机元素
random_num = nums[random_index]
return random_num
""" 扩展数组长度 """
def extend(nums, enlarge):
# 初始化一个扩展长度后的数组
res = [0] * (len(nums) + enlarge)
# 将原数组中的所有元素复制到新数组
for i in range(len(nums)):
res[i] = nums[i]
# 返回扩展后的新数组
return res
""" 在数组的索引 index 处插入元素 num """
def insert(nums, num, index):
# 把索引 index 以及之后的所有元素向后移动一位
for i in range(len(nums) - 1, index - 1, -1):
nums[i] = nums[i - 1]
# 将 num 赋给 index 处元素
nums[index] = num
""" 删除索引 index 处元素 """
def remove(nums, index):
# 把索引 index 之后的所有元素向前移动一位
for i in range(index, len(nums) - 1):
nums[i] = nums[i + 1]
""" 遍历数组 """
def traverse(nums):
count = 0
# 通过索引遍历数组
for i in range(len(nums)):
count += 1
# 直接遍历数组
for num in nums:
count += 1
""" 在数组中查找指定元素 """
def find(nums, target):
for i in range(len(nums)):
if nums[i] == target:
return i
return -1
""" Driver Code """
if __name__ == "__main__":
""" 初始化数组 """
arr = [0] * 5
print("数组 arr =", arr)
nums = [1, 3, 2, 5, 4]
print("数组 nums =", nums)
""" 随机访问 """
random_num = randomAccess(nums)
print("在 nums 中获取随机元素", random_num)
""" 长度扩展 """
nums = extend(nums, 3)
print("将数组长度扩展至 8 ,得到 nums =", nums)
""" 插入元素 """
insert(nums, 6, 3)
print("在索引 3 处插入数字 6 ,得到 nums =", nums)
""" 删除元素 """
remove(nums, 2)
print("删除索引 2 处的元素,得到 nums =", nums)
""" 遍历数组 """
traverse(nums)
""" 查找元素 """
index = find(nums, 3)
print("在 nums 中查找元素 3 ,得到索引 =", index)