6.序列!序列!

xiaoxiao2021-02-28  93

列表/元组/字符串的共同点: - 都可以通过索引得到每一个元素 - 默认索引从0开始 - 切片方法得到一个范围内的元素的集合 - 有很多共同的操作符(重复操作符/拼接操作符/成员关系操作符)

list():把可迭代对象转换为列表

help(list)见下: class list(object) | list() -> new empty list | list(iterable) -> new list initialized from iterable's items | | Methods defined here: | | __add__(...) | x.__add__(y) <==> x+y | | __contains__(...) | x.__contains__(y) <==> y in x | | __delitem__(...) | x.__delitem__(y) <==> del x[y] | | __delslice__(...) | x.__delslice__(i, j) <==> del x[i:j] | | Use of negative indices is not supported. | | __eq__(...) 【例】 >>> a = list() >>> a [] >>> >>> b = 'I love fishC' >>> b = list(b) >>> b ['I', ' ', 'l', 'o', 'v', 'e', ' ', 'f', 'i', 's', 'h', 'C'] >>>

tuple:把可迭代对象转换成元组

help(tuple)见下: class tuple(object) | tuple() -> empty tuple | tuple(iterable) -> tuple initialized from iterable's items | | If the argument is a tuple, the return value is the same object. | | Methods defined here: | | __add__(...) | x.__add__(y) <==> x+y | | __contains__(...) | x.__contains__(y) <==> y in x | | __eq__(...) | x.__eq__(y) <==> x==y | | __ge__(...) | x.__ge__(y) <==> x>=y | | __getattribute__(...) 【例】 >>> a = tuple() >>> a () >>> >>> b = 'I love fishC' >>> b = tuple(b) >>> b ('I', ' ', 'l', 'o', 'v', 'e', ' ', 'f', 'i', 's', 'h', 'C') >>>

str:把参数转换成字符串

help(str)见下: class str(basestring) | str(object='') -> string | | Return a nice string representation of the object. | If the argument is a string, the return value is the same object. | | Method resolution order: | str | basestring | object | | Methods defined here: | | __add__(...) | x.__add__(y) <==> x+y | | __contains__(...) | x.__contains__(y) <==> y in x | | __eq__(...) | x.__eq__(y) <==> x==y 【例】 >>> a = 'I love fishC' >>> str(a) 'I love fishC' >>> >>> len(a) #长度 12 >>> max(a) #返回序列或参数集合中的最大值 'v' >>> max(1,1,2,-3,4) #min()最小值 4 >>> tuple = (1,2,3,4,5) >>> max(tuple) 5 >>> min(tuple) 1 注解:使用max/min,必须保证数据类型一致 >>> t1 = (1,2,3,4) >>> sum(t1) #求总和 10 >>> sorted(t1) #排序 [1, 2, 3, 4] reversed #反转 >>> reversed(t1) <reversed object at 0x7f1c2cb10690> #返回的是一个迭代器对象 >>> list(reversed(t1)) #把迭代器对象转换成list [4, 3, 2, 1] enumerate >>> enumerate(t1) <enumerate object at 0x7f1c2cb54aa0> #返回的是一个迭代器对象 >>> list(enumerate(t1)) [(0, 1), (1, 2), (2, 3), (3, 4)] #把迭代器对象转换成list zip >>> t1 = (1,2) >>> t2 = (4,5,6,7,8) >>> zip(t1,t2) [(1, 4), (2, 5)]
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