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']