增 ===》append,extend,insert1.append ==>在列表中的最后数据添加数据。例如:In [22]: list1=['zhang',123,'li','zhao',3456]In [23]: list1Out[23]: ['zhang', 123, 'li', 'zhao', 3456]In [24]: list1.append('qing')In [25]: list1Out[25]: ['zhang', 123, 'li', 'zhao', 3456, 'qing']In [26]: list1.append(234)In [27]: list1Out[27]: ['zhang', 123, 'li', 'zhao', 3456, 'qing', 234]In [28]: list1.append(' ')In [29]: list1Out[29]: ['zhang', 123, 'li', 'zhao', 3456, 'qing', 234, ' '
extend ===》可以将一个集合中的元素逐一添加到列表中例如:In [30]: list1=['zhang',123,456]In [31]: list2=['qing',789]In [32]: list1.append(list2)In [33]: list1Out[33]: ['zhang', 123, 456, ['qing', 789]]In [34]: list1.extend(list2)In [35]: list1Out[35]: ['zhang', 123, 456, ['qing', 789], 'qing', 789
insert ===》insert(index,str)在指定位置index前插入元素str例如:In [36]: list1=['zhang','qing',12,34]In [37]: list1Out[37]: ['zhang', 'qing', 12, 34]In [38]: list1.insert(1,23)In [39]: list1Out[39]: ['zhang', 23, 'qing', 12, 34]In [40]: list1.insert(0,1)In [41]: list1Out[41]: [1, 'zhang', 23, 'qing', 12, 34]
在列表进行修改时,要通过下标对要修改的元素进行修改。例如:In [46]: list1Out[46]: [1, 'zhang', 23, 'qing', 12, 34]In [47]: list1[0]Out[47]: 1In [48]: list1[0]='zhang'In [49]: list1[0]Out[49]: 'zhang'In [50]: list1Out[50]: ['zhang', 'zhang', 23, 'qing', 12, 34]In [51]: list1[3]Out[51]: 'qing'In [52]: list1[3]='zhang'In [53]: list1[3]Out[53]: 'zhang'In [54]: list1Out[54]: ['zhang', 'zhang', 23, 'zhang', 12, 34]
python中,查找元素就是看看制定的元素是否存在,有以下四类:in/not in/index/countin(存在) ===>如果存在那么结果为true,否则为falsenot in(不存在) ===>如果不存在那么结果为true,否则false例如:In [54]: list1Out[54]: ['zhang', 'zhang', 23, 'zhang', 12, 34]In [55]: temp='zhang'In [56]: if temp in list1: ....: print('找到相同的名字了:%s'%temp) ....: else: ....: print('没有找到') ....: 找到相同的名字了:zhangnot in 的使用方法与in用法相同,这里就不再举例了。
index/count ===>index和count与字符串中的用法相同Out[57]: ['zhang', 'zhang', 23, 'zhang', 12, 34]In [58]: list1.index(23)Out[58]: 2In [59]: list1.index(12)Out[59]: 4In [60]: list1.count('zhang')Out[60]: 3In [61]: list1.count('zhang')Out[61]: 3In [62]: list1.index(23,1,3)Out[62]: 2In [63]: list1.index(23,1,2)---------------------------------------------------------------------------ValueError Traceback (most recent call last)
python 之删除元素,有以下三种方法:分别是:del ===>根据下标删除 pop ===>删除最后一个元素 remove ===>根据元素的值进行删除例如:In [64]: list1Out[64]: ['zhang', 'zhang', 23, 'zhang', 12, 34]In [65]: list1.del(0) File '
sort方法是将list按特定顺序重新排列,默认为由小到大,参数reverse=True可改为倒序,由大到小。例如:In [72]: list2=[9,3,4,7,1]In [73]: list2.sort()In [74]: list2Out[74]: [1, 3, 4, 7, 9]In [75]: list2.reverse()In [76]: list2Out[76]: [9, 7, 4, 3, 1]