小甲鱼教学笔记——元组、字符串

元组：带了枷锁的列表

• 不可被修改
• 逗号是关键，（）不是关键

1.创建和访问元组

tuple1=(1,2,3,4,5,6,7,8,9)
tuple1

(1, 2, 3, 4, 5, 6, 7, 8, 9)

tuple1[1]

2

tuple1[5:]

(6, 7, 8, 9)

tuple2=tuple1
tuple2

(1, 2, 3, 4, 5, 6, 7, 8, 9)

tuple1[1]=3#不可以被修改

---------------------------------------------------------------------------

TypeError                                 Traceback (most recent call last)

<ipython-input-6-63750aca776b> in <module>
----> 1 tuple1[1]=3#不可以被修改


TypeError: 'tuple' object does not support item assignment

temp1=(1)
temp1

1

type(temp1)

int

temp2=1,2,3
temp2

(1, 2, 3)

type(temp2)

tuple

temp1=(1,)
type(temp1)

tuple

temp=[]#空列表
temp1=()#空元组
print(type(temp),type(temp1))

<class 'list'> <class 'tuple'>

8*(8)

64

8*(8,)

(8, 8, 8, 8, 8, 8, 8, 8)

2.更新和删除元组

temp=('吴亦凡','陈晓','胡歌','黄子韬')
temp=temp[:2]+('李沁','张予曦')+temp[2:]
temp

('吴亦凡', '陈晓', '李沁', '张予曦', '胡歌', '黄子韬')

del temp#删除元组，很少用，因为python有回收机制
temp

---------------------------------------------------------------------------

NameError                                 Traceback (most recent call last)

<ipython-input-19-db4185758f4f> in <module>
      1 del temp
----> 2 temp


NameError: name 'temp' is not defined

3.可以用的相关操作符

1. 拼接操作符:temp=temp[:2]+(‘李沁’,‘张予曦’)+temp[2:]
2. 重复操作符:8*(8)
3. 关系操作符:><=
4. 逻辑操作符:or and is not …
5. 成员操作符: in ,not in

字符串：

• 各种奇怪的方法

str1='i love money'
str1[:6]

'i love'

str1[5]

'e'

str1=str1[:6]+'插入的字符串'+str1[6:]
str1

'i love插入的字符串 money'

1. capitalize():把首字母大写

str2='zheshixiaoxiezimu'
str2.capitalize()

'Zheshixiaoxiezimu'

2. casefold():全部改为小写

str2='ZHESHIxiaoxiezimu'
str2.casefold()

'zheshixiaoxiezimu'

3. center(width):居中

str2.center(50)

'                ZHESHIxiaoxiezimu                 '

4. S.count(sub[, start[, end]]) ：查找子串出现的次数

str2.count('xi')

2

5.S.endswith(suffix[, start[, end]]) -> bool:判断是否以"suffix"结束

str2.endswith('mu')

True

6. S.find(sub[, start[, end]]) -> int:寻找子串

str3="i love china"
str3.find('hh')

-1

str3.find("china")

7

7. str4.istitle():首字母大写其余小写为标题

str4="Yuhongxia"
str4.istitle()

True

8. str4.join(iterable, /):以字符串为分隔符

str4.join("123456")

'1Yuhongxia2Yuhongxia3Yuhongxia4Yuhongxia5Yuhongxia6'

9. str5.lstrip(chars=None, /):去掉左边的空格

str5="    i love you"
str5.lstrip()

'i love you'

10. str5.partition(sep, /):分割

str5.partition("ov")

('    i l', 'ov', 'e you')

11. str5.replace(old, new, count=-1, /)：替换

str5.replace("you","myself")

'    i love myself'

12. str5.split(sep=None, maxsplit=-1):吧字符串以“step”为界，切割为列表

str5.split()

['i', 'love', 'you']

str5.split('o')

['    i l', 've y', 'u']

13. str6.strip(chars=None, /):删掉指定字符串，默认空格

str6="          ssssssssssyyyyyyyyyyyyssssssuuu"
str6.strip()

'ssssssssssyyyyyyyyyyyyssssssuuu'

str6.strip("ssssss")

'          ssssssssssyyyyyyyyyyyyssssssuuu'