Python——》for循环、list列表、浅拷贝、深拷贝

原创已于 2025-12-03 09:20:41 修改 · 138 阅读

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于 2025-11-24 16:26:24 首次发布

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1、循环遍历

"""for循环语法使用"""
for i in range(0,5):
    print(f"输出:{i}")

"""指定循环次数"""
for i in range(5):
    print(i)

"""遍历字符串的每一个字符"""
test_a = "123abcAbf"
for i in test_a:
    print(i)

"""遍历列表"""
test_b = ['张三','李四','王五']
for i in test_b:
    print(i)

"""遍历步长"""
for i in range(10,20,2):
    print(i)

"""遍历反向取步长"""
for i in range(20,10,-2):
    print(i)

运行结果：

D:\Study\pythonProject\venv\Scripts\python.exe D:/Study/pythonProject/Test1124.py
输出:0
输出:1
输出:2
输出:3
输出:4
0
1
2
3
4
1
2
3
a
b
c
A
b
f
张三
李四
王五
10
12
14
16
18
20
18
16
14
12

Process finished with exit code 0

2、列表

"""列表"""
a = [1,2,3]
"""输出第一个"""
print(f'第一个：{a[0]}')
"""输出前两个"""
print(a[:1])
"""输出列表长度"""
print(len(a))
"""修改列表"""
a[1]='b'
print(a)
"""列表与列表的合并"""
b = [4,5,6]
c = b+a
print(c)
# """列表与字符串不能合并,会报异常"""
# aa = '李四'
# bb = [1,2,3]
# cc = aa + bb
# print(cc)

"""列表通用函数"""
"""len()/min()/max()/sum()"""
user_list = [1,2,3,4,5,6]
print(len(user_list))
print(min(user_list))
print(max(user_list))
print(sum(user_list))
print(sum(user_list)/len(user_list))

"""列表内置方法"""
"""append()添加元素"""
a_list = [1,2,3,4]
a_list.append('b')
a_list.append(['a','d','f',])
print(a_list)

"""clear()清除"""
b_list = [1,2,3,4,5,6]
b_list.clear()
print(b_list)

"""count()计数"""
c_list = [22,33,44,55,66,77,88]
print(c_list.count(55))

"""extend()扩展列表"""
c_list = [22,33,44,55,66,77,88]
c_list.extend([1111,2222])
print(c_list)

"""index(Value,[start,[stop]])下标"""
c_list = [22,33,44,55,66,77,88]
print('第1个55在哪里：',c_list.index(55))
print('从第二个开始找，第1个55在哪里：',c_list.index(55,2))

"""insert(index,object)插入对象"""
c_list = [22,33,44,55,66,77,88]
c_list.insert(2,'A')
c_list.insert(-2,[33333333])
print(c_list)

"""pop(index)/remove()/del删除元素"""
c_list = [22,33,44,55,66,77,88]
print('删除对应下标的值',c_list.pop(3))
c_list.remove(22)
print('删除对应的值',c_list)
del c_list[2]
print('删除指定的值',c_list)

"""sort()排序"""
d_list = [22,33,44,55,66,77,88]
d_list.sort(reverse=True)
print('降序',d_list)
d_list.sort(reverse=False)
print('升序',d_list)

运行结果：

D:\Study\pythonProject\venv\Scripts\python.exe D:/Study/pythonProject/Test1124.py
第一个：1
[1]
3
[1, 'b', 3]
[4, 5, 6, 1, 'b', 3]
6
1
6
21
3.5
[1, 2, 3, 4, 'b', ['a', 'd', 'f']]
[]
1
[22, 33, 44, 55, 66, 77, 88, 1111, 2222]
第1个55在哪里： 3
从第二个开始找，第1个55在哪里： 3
[22, 33, 'A', 44, 55, 66, [33333333], 77, 88]
删除对应下标的值 55
删除对应的值 [33, 44, 66, 77, 88]
删除指定的值 [33, 44, 77, 88]
降序 [88, 77, 66, 55, 44, 33, 22]
升序 [22, 33, 44, 55, 66, 77, 88]

Process finished with exit code 0

3、浅拷贝、深拷贝

"""copy()浅拷贝"""
d_list = [22,33,44,55,66,77,88]
e_list = d_list.copy()
e_list[0] = 1
print(d_list)
print(e_list)

"""deepcopy()深拷贝"""
import copy
f_list = [22,33,[44],55,66,77,88]
g_list = copy.deepcopy(f_list)
g_list[2][0] = 0
print(f_list)
print(g_list)

运行结果：

[22, 33, 44, 55, 66, 77, 88]
[1, 33, 44, 55, 66, 77, 88]
[22, 33, [44], 55, 66, 77, 88]
[22, 33, [0], 55, 66, 77, 88]