2018-10-23

列表

前面两篇文章关于Python最基础的数据,今天这篇文章的主题是列表。

列表用于有序存储数据,包括数字、字母、字符串等。

(1)创建与打印列表

smart_products=['computer','phone','television']

print(smart_products)

运行结果:

['computer','phone','television']

打印列表元素:

print(smart_products[0])

运行结果:

computer

打印列表元素:

print(smart_products[-1])

运行结果:

television

(2)修改列表元素

smart_products=['computer','phone','television']

smart_products[1]='tablet'

print(smart_products)

运行结果:

['computer','tablet','television']

(3)添加列表元素

smart_products=['computer','phone','television']

smart_products.append('tablet')

print(smart_products)

运行结果:

['computer','phone','television','tablet']

插入元素:

smart_products=['computer','phone','television']

smart_products.insert(1,'tablet')

print(smart_products)

运行结果:

['computer','tablet','phone','television']

(4)删除列表元素

smart_products=['computer','phone','television']

del smart_products[1]

print(smart_products)

运行结果:

['computer','television']

弹出列表元素:

smart_products=['computer','phone','television']

popped_product=smart_products.pop()

print(smart_products)

print(popped_product)

运行结果:

['computer','phone']

television

根据索引弹出列表元素:

smart_products=['computer','phone','television']

popped_product=smart_products.pop(1)

print(smart_products)

print(popped_product)

运行结果:

['computer','television']

phone

根据值弹删除出列表元素:

smart_products=['computer','phone','television']

removed_product='television'

smart_products.remove(removed_product)

print(smart_products)

print(removed_product)

运行结果:

['computer','phone']

television

(4)列表排序

按字母顺序排序:

internet_giants=['baidu','alibaba','tencent','google','ibm','microsoft','lenovo','apple']

internet_giants.sort()

print(internet_giants)

运行结果:

['alibaba','apple','baidu','google','ibm','lenovo','microsoft','tencent']

倒着按字母顺序排序:

internet_giants=['baidu','alibaba','tencent','google','ibm','microsoft','lenovo','apple']

internet_giants.sort(reverse=True)

print(internet_giants)

运行结果:

['tencent','microsoft','lenovo','ibm','google','baidu','apple','alibaba']

临时按字母顺序排序:

internet_giants=['baidu','alibaba','tencent','google','ibm','microsoft','lenovo','apple']

internet_giants_1=sorted(internet_giants)

print(internet_giants)

print(internet_giants_1)

运行结果:

['baidu','alibaba','tencent','google','ibm','microsoft','lenovo','apple']

['alibaba','apple','baidu','google','ibm','lenovo','microsoft','tencent']

倒着按字母顺序临时排序:

internet_giants=['baidu','alibaba','tencent','google','ibm','microsoft','lenovo','apple']

internet_giants_1=sorted(internet_giants,reverse=True)

print(internet_giants)

print(internet_giants_1)

运行结果:

['baidu','alibaba','tencent','google','ibm','microsoft','lenovo','apple']

['tencent','microsoft','lenovo','ibm','google','baidu','apple','alibaba']

翻转列表:

internet_giants=['baidu','alibaba','tencent','google','ibm','microsoft','lenovo','apple']

internet_giants.reverse()

print(internet_giants)

运行结果:

['apple','lenovo','microsoft','ibm','google','tencent','alibaba','baidu']

(5)计算列表长度

internet_giants=['baidu','alibaba','tencent','google','ibm','microsoft','lenovo','apple']

length=len(internet_giants)

print(length)

运行结果:

8

(6)使用for循环遍历整个列表

注意缩进和冒号

cities=['shanghai','paris','london','new york']

for city in cities:

    print(city.title())

运行结果:

Shanghai

Paris

London

New York

(7)使用range()和list()创建数值列表

注意边界

for number in range(1,7):

    print(number )

运行结果:

1

2

3

4

5

6

创建列表:

numbers=[]

for number in range(1,5):

    numbers.append(number )

print(numbers)

运行结果:

[1,2,3,4]

使用list()创建列表:

print(list(range(1,5)))

运行结果:

[1,2,3,4]

指定步长:

print(list(range(1,10,2)))

运行结果:

[1,3,5,7,9]

(8)统计列表

numbers=list(range(1,10))

print(min(numbers))

print(max(numbers))

print(sum(numbers))

运行结果:

1

9

45

(9)列表解析

numbers=[n**3 for n in range(1,5)]

print(numbers)

运行结果:

1

8

27

64

(10)列表切片与列表复制

列表切片:

fruits=['apple','banana','grape','orange']

fruits_1=fruits[1:3]

fruits_2=fruits[1:]

fruits_3=fruits[:3]

fruits_4=fruits[-2:]

print(fruits)

print(fruits_1)

print(fruits_2)

print(fruits_3)

print(fruits_4)

运行结果:

['apple','banana','grape','orange']

['banana','grape']

['banana','grape','orange']

['apple','banana','grape']

['grape','orange']

复制列表:

使用切片而非列表名复制列表:

fruits=['apple','banana','grape','orange']

fruits_1=fruits[:]

fruits_1.append('cherry')

print(fruits_1)运行结果:

['apple','banana','grape','orange','cherry']

今天信息量有点大,回顾了列表的创建、改变、添加、删除,列表本身的排序与字母排序,列表长度的计算,列表的循环遍历,数值列表的创建、简单统计,列表的解析,列表切片与复制。其中,重要的几点有,for循环,del语句,方法append()、insert()、pop()、remove()、sort()、reverse(),函数sorted()、len()、min()、max()、sum()、range()、list()。这些函数和方法在以后的学习中也会经常用到。

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