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第四章 操作列表

时间:2019-06-05 00:14:59      阅读:104      评论:0      收藏:0      [点我收藏+]

标签:dimen   list   lin   缩进   创建序列   处理   alice   引用   格式   

4.1 遍历整个列表:for循环

注意:使用单数和复数式名称, 可帮助你判断代码段处理的是单个列表元素还是整个列表。

循环语句的冒号不可省略,循环体部分需要统一缩进

01 # ex1

02 magicians = [‘alice‘, ‘david‘, ‘carolina‘]

03 for magician in magicians:

04 print(magician)

05 print("\n")

06

07 # ex2

08 for magician in magicians:

09 print(magician.title()+",that was a great trick!");

10 print("I can‘t wait to see you next trick,"+magician.title()+".\n");

>>>

alice

david

carolina

? ?

? ?

Alice,that was a great trick!

I can‘t wait to see you next trick,Alice.

? ?

David,that was a great trick!

I can‘t wait to see you next trick,David.

? ?

Carolina,that was a great trick!

I can‘t wait to see you next trick,Carolina.

? ?

4.2 创建数值列表

  • 利用range(num1,num2)函数

    函数range() 让Python从你指定的第一个值开始数, 并在到达你指定的第二个值后停止, 因此输出不包含第二个值

  • 使用range()创建数字列表:

    使用函数list() 将range() 的结果直接转换为列表。 如果将range() 作为list() 的参数, 输出将为一个数字列表

  • 利用range()函数创建任意列表

01 # ex3

02 for value in range(1,6):

03 print(value);

04

05 number=list(range(1,6));

06 print(number);

07

08

09 number1=list(range(2,11,2));

10 print(number1);

11

12 # squares.py

13 squares=[];

14 for value in range(1,11):

15 square=value**2

16 squares.append(square)

17 print(squares)

18

19 # squares.py/ another tips

20 squares=[]

21 for value in range(1,11):

22 squares.append(value**2);

23 print(squares);

? ?

>>>

1

2

3

4

5

[1, 2, 3, 4, 5]

[2, 4, 6, 8, 10]

[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

4.3 对数字列表进行简单的统计计算

  • min()函数、max()函数以及sum()函数
  • 列表解析(快速创建序列)

01 # ex4.3

02 num=list(range(0,10));

03 print(num);#test

04 del num[0];

05 num.append(0);

06 print(num);#over test

07 a=min(num);

08 b=max(num);

09 c=sum(num);

10 print("the minmum number is "+str(a)+"\nthe maxmum number is "+str(b));

11 print("the sumarise number is "+str(c));

12

13 #ex 4.3.3

14 squares1=[value**2 for value in range(1,11)];

15 print(squares1);

>>>

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

[1, 2, 3, 4, 5, 6, 7, 8, 9, 0]

the minmum number is 0

the maxmum number is 9

the sumarise number is 45

[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

4.4 使用列表的一部分

  • 切片:通过在序列引用后面加上":"
  • 复制列表:确定是否使用切片复制列表,如果是非切片形式创建的列表,则实际上在共用一个列表存储,改变一个其中一个随之改变;反之以切片形式创建的列表,则会创建两个不同列表。

01 # foods.py

02 my_foods=["pizza","falafel","carrot cake"];

03 friend_foods=my_foods[:];

04 my_foods.append("cannoli");

05 friend_foods.append("ice cream");

06 print("my favorite foods are ");

07 print(my_foods);

08 print("my favorite foods are ");

09 print(friend_foods);

10

11 # 非切片

12 print("\n

");

14 my_foods=["pizza","falafel","carrot cake"];

15 friend_foods=my_foods;

16 my_foods.append("cannoli");

17 friend_foods.append("ice cream");

18 print("my favorite foods are ");

19 print(my_foods);

20 print("my favorite foods are ");

21 print(friend_foods);

>>>

my favorite foods are

[‘pizza‘, ‘falafel‘, ‘carrot cake‘, ‘cannoli‘]

my favorite foods are

[‘pizza‘, ‘falafel‘, ‘carrot cake‘, ‘ice cream‘]

? ?

? ?

my favorite foods are

[‘pizza‘, ‘falafel‘, ‘carrot cake‘, ‘cannoli‘, ‘ice cream‘]

my favorite foods are

[‘pizza‘, ‘falafel‘, ‘carrot cake‘, ‘cannoli‘, ‘ice cream‘]

? ?

4.5 元组

目的:创建一系列不可修改的元素,但是可以对整个元组重新进行定义

创建方式:各个元素用()包括取代列表的[]。

01 dimentions=(200,50);

02 print("orginal dimention");

03 for dimention in dimentions:

04 print(dimention);

>>>

orginal dimention

200

50

4.6 设置代码格式:PEP8

第四章 操作列表

标签:dimen   list   lin   缩进   创建序列   处理   alice   引用   格式   

原文地址:https://www.cnblogs.com/lovely-bones/p/10976745.html

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