python 数据类型---列表使用之三

1. 判断列表中是否存在一个元素： "in" 的使用

list = ['Frank', 99, 'is',78, 7,3,4,'smart']
print(99 in list)
print(9 in list)

#运行结果
True
False

2. 元素个数统计： count

>>> name = ['',4,45,4343,34,56,6,7,5,3,9]
>>> name.count(9)
1
>>> name.count(3)
1
>>>

3.元素位置索引： index（
    L.index(value, [start, [stop]]) -> integer -- return first index of value.
    Raises ValueError if the value is not present.）

list = ['Frank', 99, 'is',78, 7,3,4,'smart',9,939,84,83,9]
print(99 in list)
print(9 in list)
#count 使用
num_of_ele = list.count(9)
#index 使用
posistion_of_ele = list.index(9)
print("[%s] 9 in list , posistion is [%s]" %(num_of_ele, posistion_of_ele))

#测试结果
True
True
[2] 9 in list , posistion is [8]

4. 列表的扩展 ： extend

name = ["frank", "Malon","Lee"]
name2 = ["Andy", "Troy"]
name.extend(name2)
print(name)
print(name2)

#运行结果
['frank', 'Malon', 'Lee', 'Andy', 'Troy']
['Andy', 'Troy']

5. 列表的拷贝：copy #  L.copy() -> list -- a shallow copy of L 只进行肤浅的拷贝

name = ['alex','Rain','Erik',['a','b','c'],'Frank']
name3 = name.copy()
print("测试一")
print(name)
print(name3)

print("测试二")
name[0] = 'ALEX'
print(name)
print(name3)

print("测试三")
name[3][0] = 'AAAAAA'
print(name)
print(name3)

print("测试四")
name3[3][2] = 'CCCCCC'
print(name)
print(name3)

#测试结果
测试一
['alex', 'Rain', 'Erik', ['a', 'b', 'c'], 'Frank']
['alex', 'Rain', 'Erik', ['a', 'b', 'c'], 'Frank']
测试二
['ALEX', 'Rain', 'Erik', ['a', 'b', 'c'], 'Frank']
['alex', 'Rain', 'Erik', ['a', 'b', 'c'], 'Frank']
测试三
['ALEX', 'Rain', 'Erik', ['AAAAAA', 'b', 'c'], 'Frank']
['alex', 'Rain', 'Erik', ['AAAAAA', 'b', 'c'], 'Frank']
测试四
['ALEX', 'Rain', 'Erik', ['AAAAAA', 'b', 'CCCCCC'], 'Frank']
['alex', 'Rain', 'Erik', ['AAAAAA', 'b', 'CCCCCC'], 'Frank']

6. 列表copy---deepcopy （import copy）

import copy
name = ['alex','Rain','Erik',['a','b','c'],'Frank']
name3 = name.copy()
name4 = copy.deepcopy(name)
print("测试一")
print(name)
print(name3)
print(name4)

name[3][1] = 'AAAAAAAA'
print("测试二")
print(name)
print(name3)
print(name4)

#测试结果
测试一
['alex', 'Rain', 'Erik', ['a', 'b', 'c'], 'Frank']
['alex', 'Rain', 'Erik', ['a', 'b', 'c'], 'Frank']
['alex', 'Rain', 'Erik', ['a', 'b', 'c'], 'Frank']
测试二
['alex', 'Rain', 'Erik', ['a', 'AAAAAAAA', 'c'], 'Frank']
['alex', 'Rain', 'Erik', ['a', 'AAAAAAAA', 'c'], 'Frank']
['alex', 'Rain', 'Erik', ['a', 'b', 'c'], 'Frank']