pandas 遍历有以下三种访法. iterrows():在单独的变量中返回索引和行项目,但显着较慢 itertuples():快于.iterrows(),但将索引与行项目一起返回,ir [0]是索引 zip:最快,但不能访问该行的索引 df= pd.DataFrame({'a': range(0, 10000), 'b': range(10000, 20000)}) 0.for i in df:并不是遍历行的方式 for i in df: print(i) 正式因为for in df不是直接遍
通过NPOI对Excel进行操作,这里主要是读取的操作.封装到ExcelHelper操作类中. 1 using System.Collections.Generic; 2 using NPOI.HSSF.UserModel; 3 using NPOI.SS.UserModel; 4 using NPOI.XSSF.UserModel; 5 using System.IO; 6 using System.Data; 7 using System; 8 9 namespace CommonHelpe
一定要自己试过才知道么? 你也没试过吃屎,你怎么知道屎不能吃,难道你试过啊...(没有愤怒的意思) ),),) declare cursor_data CURSOR FOR SELECT [UserName],[Email],[LastLoginIP] FROM [dbo].[Users] --数据源 open cursor_data fetch from cursor_data into @name,@email,@LastLoginIP --遍历一行值 begin print @name -
1.巧用for循环计数,将文件每10行写到另一个文件,每遍历一行i就加1 with open('/etc/passwd') as f1, open('/tmp/passwd','w') as f2: i = 0 for line in f1: i += 1 if i % 10 == 0: print line, f2.write(line) 2.打印图形 count = 1 while count < 6: print count * '*' count += 1 for line in ran
思路:重开一个新图,按着邻接列表的顺序从上到下遍历,每遍历一行链表前,清空visited数组,如果没有访问过这个元素,则加入新图,如果已经访问过了(重边),则不动. 伪代码: 复杂度:O(V+E) for each u 属于 Vertex visited[u] = false; for u 属于 Vertex visited[u] = true; for v 属于 Adj[u] if(!visited[v]) Adj1[u].insert(v); visited[v] = true; for v
本文是在学习中的总结,欢迎转载但请注明出处:http://blog.csdn.net/pistolove/article/details/41851069 Given an index k, return the kth row of the Pascal's triangle. For example, given k = 3,Return [1,3,3,1]. Note:Could you optimize your algorithm to use only O(k) extra spac