Python-数据类型

1、布尔类型

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3、列表

3.1、定义个列表

>>> names = ["cwb","cjl","cwz","wangyan"]

>>> names

['cwb', 'cjl', 'cwz', 'wangyan']

>>> print(names)

['cwb', 'cjl', 'cwz', 'wangyan']

 

3.2、查看列表内容

列表里的内容有索引值， ["cwb","cjl","cwz","wangyan"] 分别对应[0,1,2,3]

>>> names[-1]

'wangyan'

>>> names[1]

'cjl'

 

3.3、追加-append，

>>> names.append("cwd") #默认追加到最后

>>> names

['cwb', 'cjl', 'cwz', 'wangyan', 'cwd', 'cwd']

 

3.4、插入 names.insert(插入位置的索引号，“字符”)

names.insert

 

在 cwd前面插入lyq

>>> names

['cwb', 'cjl', 'cwz', 'wangyan', 'cwd']

>>> names.insert(4,"lyq")

>>> names

['cwb', 'cjl', 'cwz', 'wangyan', 'lyq', 'cwd']

 

在 cwd后面插入cwp

>>> names

['cwb', 'cjl', 'cwz', 'wangyan', 'lyq', 'cwd']

>>> names.insert(6,"cwp")

>>> names

['cwb', 'cjl', 'cwz', 'wangyan', 'lyq', 'cwd', 'cwp']

 

3.5、从字符串中删除，del names[索引]

删除cwp

>>> names

['cwb', 'cjl', 'cwz', 'wangyan', 'lyq', 'cwd', 'cwp']

>>> del names[6]

>>> names

['cwb', 'cjl', 'cwz', 'wangyan', 'lyq', 'cwd']

 

3.6、从字符串中删除，names.remove("字符")

删除lyq

>>> names

['cwb', 'cjl', 'cwz', 'wangyan', 'lyq', 'cwd']

>>> names.remove("lyq")

>>> names

['cwb', 'cjl', 'cwz', 'wangyan', 'cwd']

 

3.7

3.7.1、修改字符串内的内容，names[索引] = “修改后的内容”

将cwd改成 dz，先查cwd的索引，再修改值

>>> names

['cwb', 'cjl', 'cwz', 'wangyan', 'cwd']

>>> names.index("cwd")

4

>>> names[4] = "dz"

>>> names

['cwb', 'cjl', 'cwz', 'wangyan', 'dz']

 

3.7.2、直接修改

>>> names

['cwb', 'cjl', 'cwz', 'wangyan', 'dz']

>>> names[names.index("dz")] = "cwd"

>>> names

['cwb', 'cjl', 'cwz', 'wangyan', 'cwd']

 

3.8 统计数量 names.count("字符")

>>> names.append("cwb")

>>> names

['cwb', 'cjl', 'cwz', 'wangyan', 'cwd', 'cwb']

>>> names.count("cwb")

2

 

3.9、排序 names.sort()

>>> names

['cwb', 'cjl', '5', 'Db', 'Db', 'db', 'wangyan', 'cwd', 'cwb']

>>> names.sort() #正序排，按照asscii排序

>>>

>>> names

['5', 'Db', 'Db', 'cjl', 'cwb', 'cwb', 'cwd', 'db', 'wangyan']

>>> names.reverse() #倒叙排

>>> names

['wangyan', 'db', 'cwd', 'cwb', 'cwb', 'cjl', 'Db', 'Db', '5']

 

3.10、取值 --从左向右

>>> names[3:6]

['cwb', 'cwb', 'cjl']

>>> names[:6]

['wangyan', 'db', 'cwd', 'cwb', 'cwb', 'cjl']

>>> names[-3:]

['Db', 'Db', '5']

 

>>> names

['wangyan', 'db', 'cwd', 'cwb', 'cwb', 'cjl', 'Db', 'Db', '5']

>>> names[3:6:2] #步长为2，取3-6的值，每次步长为2

['cwb', 'cjl']

>>>

>>> names[0:-1:2]

['wangyan', 'cwd', 'cwb', 'Db']