python3基础--列表和字典

Posted 2020-10-24 truthk

列表

name = [‘kzx‘, ‘666‘, ‘none‘, ‘truth‘]

# 截取
print(name[1: 3])  # 取下标1到3的元素(含下标1的元素,但是不包含3的)
[‘666‘, ‘none‘]
print(name[1:-1])  # 也是取下标1到-1(即下标3)的元素(含下标1的元素,但是不包含-1的)
[‘666‘, ‘none‘]

print(name[0:3])  # 取下标0到3的元素(含下标1的元素,但是不包含3的)
[‘kzx‘, ‘666‘, ‘none‘]
print(name[:3])   # 也是取下标0到3的元素
[‘kzx‘, ‘666‘, ‘none‘]

print(name[1:])   # 取除下标0外所有的元素
[‘666‘, ‘none‘, ‘truth‘]
print(name[1: 4])  # 当下标大于该列表的最大下标时,等价于name[start,max]
                   # (start即开始取的下标,max即该列表最大的下标)
[‘666‘, ‘none‘, ‘truth‘]


# 添加
name.append("new")  # 从最后添加
name.insert(2, "插入")
print(name)
[‘kzx‘, ‘666‘, ‘插入‘, ‘none‘, ‘truth‘, ‘new‘]

# 修改
name[2] = "change"
print(name)
[‘kzx‘, ‘666‘, ‘change‘, ‘none‘, ‘truth‘, ‘new‘]

# 删除
del name[2]  # 删除列表下标为2的元素
name.remove("kzx")  # 指定删除元素
print(name)
[‘666‘, ‘none‘, ‘truth‘, ‘new‘]
name.pop()  # 删除列表最后一个值

# 合并2个列表
b = [1, 2, 3]
name.extend(b)
print(name)
[‘666‘, ‘none‘, ‘truth‘, 1, 2, 3]

# copy
copy_name = name.copy()
print(copy_name)
[‘666‘, ‘none‘, ‘truth‘, 1, 2, 3]

# 统计元素出现次数
names = [‘kkk‘, ‘rr‘, ‘kkk‘, ‘e‘, ‘rr‘, 1, 2, 3]
print(names.count("kkk"))
2

# 排序
c = [1, 2, 3]
c.sort()
print(c)  # python3里不同数据类型不能放在一起排序
[1, 2, 3]

c.reverse()
print(c)  # 反转
[3, 2, 1]

# 获取下标
print(names.index("kkk"))  # 只返回找到的第一个下标
0

字典

dic = {‘name‘: ‘a‘, ‘age‘: 21, ‘gender‘: ‘middle‘}

# 添加
dic[‘habbit‘] = ‘a_lot‘
print(dic)
{‘name‘: ‘a‘, ‘gender‘: ‘middle‘, ‘habbit‘: ‘a_lot‘, ‘age‘: 21}

# 修改
dic[‘habbit‘] = ‘none‘
print(dic)
{‘name‘: ‘a‘, ‘gender‘: ‘middle‘, ‘habbit‘: ‘none‘, ‘age‘: 21}

# 删除
dic.pop(‘habbit‘)  # or use (del dic[‘habbit‘])
print(dic)
{‘name‘: ‘a‘, ‘gender‘: ‘middle‘, ‘age‘: 21}

# 查找
print(‘age‘ in dic)
True
print(dic.get(‘age‘))  # or use (dic[‘age‘])
21

# others
print(dic.values())
print(dic.keys())
dict_values([‘a‘, ‘middle‘, 21])
dict_keys([‘name‘, ‘gender‘, ‘age‘])

# 遍历
# 方法1
for key in dic:
    print(key, dic[key])

# 方法2
for k, v in dic.items():  # 会先把dict转成list,数据里大时莫用
    print(k, v)

弱渣的我介绍一下python3的列表和字典,还有稍微提一下元组

关于元组

names = ("al","u","c")

元组其实跟列表差不多，也是存一组数，只不是它一旦创建，便不能再修改，所以又叫只读列表

[1, 2, 3][3, 2, 1]