python 列表操作

列表生成式:

a=[x*x for x in range(10)]#等价[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]


索引(下标) ,都是从0开始
切片
.count 查某个元素的出现次数
.index 根据内容找其对应的位置
"x" in a
增加
a.append() 追加
a.insert(index, "内容")
a.extend 扩展

修改
a[index] = "新的值"
a[start:end] = [a,b,c]

删除
remove("内容")
pop(index)
del a, del a[index]
a.clear() 清空

排序
sort ()
reverse()

身份判断
>>> type(a) is list
True

切片:

a=['0','1','2','3','4','5','6']

print(1,a[:]) #all
print(2,a[0:])
print(3,a[0:-1])#最后一个不取
print(4,a[0:7])#和range类似
print(5,a[0:6:2])
print(6,a[0::2])
print(7,a[::-1])#逆置
print(8,a[6::-1])
print(9,a[6::-2])
print(10,a[:0:-2])#取不到0
print(11,a[-1::-2])
1 ['0', '1', '2', '3', '4', '5', '6']
2 ['0', '1', '2', '3', '4', '5', '6']
3 ['0', '1', '2', '3', '4', '5']
4 ['0', '1', '2', '3', '4', '5', '6']
5 ['0', '2', '4']
6 ['0', '2', '4', '6']
7 ['6', '5', '4', '3', '2', '1', '0']
8 ['6', '5', '4', '3', '2', '1', '0']
9 ['6', '4', '2', '0']
10 ['6', '4', '2']
11 ['6', '4', '2', '0']

增加:(append、insert)

a=['0','1']
a.append(2)
print(a)
a.insert(1,"123")
print(a)
['0', '1', 2]
['0', '123', '1', 2]

修改:

a=['0','1','2']
a[1]=2
print(a)
a[0:2]=['a','b']
print(a)
['0', 2, '2']
['a', 'b', '2']

删除:(remove、pop、del)

a=['0','1','2','1','3']
a.remove('1')
print(a)
b=a.pop(1)
print(b)
print(a)
del a[0]
print(a)
a.clear()#清空列表
['0', '2', '1', '3']
2
['0', '1', '3']
['1', '3']

 

列表内置的important方法:

a=['0','1','2','1','3']
b=['1','2','3']
print(a.count('1'))#计算元素出现次数
print(a.index('1'))#找到特定元素的位置

a.extend(b) #把b中元素添加到a中元素
print(a)

a.reverse() # 逆置
print(a)

a.sort() #排序
print(a)
2
1
['0', '1', '2', '1', '3', '1', '2', '3']
['3', '2', '1', '3', '1', '2', '1', '0']
['0', '1', '1', '1', '2', '2', '3', '3']

 

随便用
原文地址:https://www.cnblogs.com/pqhuang/p/11193762.html