循环写入多个CSV文件 [英] Write Multiple CSV files in a loop

问题描述

我有一个具有150万行的csv文件，该文件由2列名称和电子邮件组成.我想编写一个程序，以便当我在R中读取文件时，每个csv中的输出被分割成5000个数据.

I have a csv file with 1.5 million rows which consists of 2 columns name and email.I want to write a program in such way that when I read my file in R, the output is segmented of 5000 data in each csv.

也许我可以循环执行此操作:从第1行运行到5000，然后将其保存为project1.csv，然后将其保存为project1.csv，然后将其保存到project2.csv，然后在工作目录的project3.csv中保存为10001至15000.有什么建议吗?

Maybe I can do this with a loop: run from row 1 to 5000 and save it as project1.csv and then 5001 to 10000 and save to project2.csv and then 10001 till 15000 in project3.csv in my working directory. Any suggestions?

推荐答案

假设'df1'是data.frame，我们需要每隔5000行进行细分并将其保存在新文件中，我们将split数据集根据到list(lst)的行序列创建分组索引.我们遍历list元素(lapply(...)的顺序，并使用write.csv写入新文件.

Assuming that 'df1' is the data.frame which we need to segment every 5000 rows and save it in a new file, we split the dataset by creating a grouping index based on the sequence of rows to a list (lst). We loop through the sequence of list elements (lapply(...), and write new file with write.csv.

n <- 5000
lst <-  split(df1, ((seq_len(nrow(df1)))-1)%/%n+1L)
invisible(lapply(seq_along(lst), function(i) 
   write.csv(lst[[i]], file=paste0('project', i, '.csv'), row.names=FALSE)))

这篇关于循环写入多个CSV文件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！