1、列表
#1.1 切片 names = ["zhangsan","lisi","wangwu","zhuqi"] print(names[0],names[2]) #取第1个和第3个 print(names[0:3]) # 切片 取前三个 print(names[:3]) # 切片 取前三个 print(names[-1]) #取最后一个 print(names[-3:-1]) #切片 取倒数第3和倒数第2个 print(names[-3:]) #切片 取倒数1,2,3
print(names[0:-1:2]) #切片 步长为2
#1.2插入 names = ["zhangsan","lisi","wangwu","zhuqi"] names.append("新加入成员") #追加到最后 names.insert(2,"insert插入") #插入到2这个位置其他后移
#1.3修改 names = ["zhangsan","lisi","wangwu","zhuqi"] names[1] = "bobo" #将第二个成员改为bobo
#1.4删除 names = ["zhangsan","lisi","wangwu","zhuqi","wangba"] del names[1] #删除下标为1的成员 names.remove("wangwu") #删除指定成员,无返回 names.pop() #删除最后一个,返回删除成员 names.pop(1) #删除下标为1的成员 print(names)
#1.5 获取元素位置 names = ["zhangsan","lisi","wangwu","zhuqi","wangba"] names.index("lisi") #返回1
#1.6 扩展 >>> names = ["zhangsan","lisi","wangwu","zhuqi","wangba"] >>> names2 = [1,2,3] >>> names.extend(names2) >>> names ['zhangsan', 'lisi', 'wangwu', 'zhuqi', 'wangba', 1, 2, 3]
#1.7 排序 >>> names = ["zhangsan","lisi","wangwu","zhuqi","wangba"] >>> names2 = [3,5,4,2,1] >>> names.sort(reverse=True) #降序 >>> names2.sort() #升序,默认reverse=False >>> names ['zhuqi', 'zhangsan', 'wangwu', 'wangba', 'lisi'] >>> names2 [1, 2, 3, 4, 5]
#1.8 copy 浅copy和深copy >>> names = ["zhangsan","lisi","wangwu",[1,2,3],"zhuqi"] >>> names2 = names.copy() #等同names2=names[:] 或 names2 = copy.copy(names)或 names2 = list(names) 浅copy >>> names ['zhangsan', 'lisi', 'wangwu', [1, 2, 3], 'zhuqi'] >>> names2 ['zhangsan', 'lisi', 'wangwu', [1, 2, 3], 'zhuqi'] >>> names[2]="香蕉" >>> names[3][0]="苹果" >>> names ['zhangsan', 'lisi', '香蕉', ['苹果', 2, 3], 'zhuqi'] >>> names2 ['zhangsan', 'lisi', 'wangwu', ['苹果', 2, 3], 'zhuqi'] #深copy 完全独立 import copy names = ["zhangsan","lisi","wangwu",[1,2,3],"zhuqi","wangba"] names2 = copy.deepcopy(names) print(names) print(names2) names[2]="香蕉" names[3][0] = "苹果" print(names) print(names2)
#1.9 count函数 >>> names = ["zhangsan","lisi","lisi"] >>> names.count("lisi") 2
2、元组
一旦创建,便不能再修改,可以理解成只读列表
>>> names = ("zhangsan","lisi","wangwu") >>> names[0] 'zhangsan' >>> names.index("lisi") 1 >>> names.count("wangwu") 1 >>>
它只有2个方法,一个是count,一个是index
3、字典
字典一种key:value 的数据类型
语法:
>>> dict={"s1":"zhangsan","s2":"lisi","s3":"wangwu"} #创建 >>> dict {'s1': 'zhangsan', 's2': 'lisi', 's3': 'wangwu'} >>> dict["s2"] #查看 'lisi'
>>>s2 in dict
>>>True
>>>dict.get("s2")
>>>"lisi" >>> dict["s2"]="wangba" #修改 >>> dict {'s1': 'zhangsan', 's2': 'wangba', 's3': 'wangwu'} >>> dict["s4"]="new_s" #增加 >>> dict {'s1': 'zhangsan', 's2': 'wangba', 's3': 'wangwu', 's4': 'new_s'} >>> del dict["s1"] #删除 >>> dict {'s2': 'wangba', 's3': 'wangwu', 's4': 'new_s'} >>> dict.pop("s2") #删除 'wangba' >>> dict {'s3': 'wangwu', 's4': 'new_s'}
字典循环
info = { 's1': "zhangsan", 's2': "lisi", 's3': "wangwu", } for key in info: #建议 print(key,info[key]) for k,v in info.items(): #不建议,效率低 print(k,v)