在 ML(SMLNJ) 中打开文件 [英] Open file in ML(SMLNJ)

问题描述

我需要在 ML (SLMNJ) 中读取文件并将其保存在某些结构中.我需要读取一些指向图声明的数据:

I need to read file in ML (SLMNJ) and save it in some structures. I need to read some data that points to graph declaration:

[( 1 , 2 , 13 ),( 2 , 3 , 3 ),( 2 , 4 , 8 ),( 2 , 5 , 4 ),( 3 , 1 , 5 ),( 3 , 4 , 1 ),( 4 , 6 , 5 ),( 5 , 5 , 5 ),( 6 , 4 , 6 )]

(第一个数字:节点名称，第二个数字:连接节点名称，第三个数字权重为这个鬃毛(每个()显示一个鬃毛))

(first number: name of the node , secend number: name of connected node , third number weight for this mane (each () show one mane ) )

例如，这是测试输入如何读取文件以及保存文件的结构

for expamle this is test input how to read file and which structure to save it

推荐答案

对于从文件中读取，请按照此到每行字符串列表:

for reading from file follow this to list of string per line :

val infile = "c:/input.txt" ;

fun readlist (infile : string) = let 

  val ins = TextIO.openIn infile 

  fun loop ins = 

   case TextIO.inputLine ins of 

      SOME line => line :: loop ins 

    | NONE      => [] 

in 

  loop ins before TextIO.closeIn ins 

end ;

val pureGraph =  readlist(infile);

并且使用此函数您可以将其解析为元组 (x,y,z) :

and with this function you can parse it to tuple (x,y,z ) :

fun creatGraph([],reList) = reList

|creatGraph(x::y::z::input,reList) =  creatGraph(input,reList@[(x,y,z)]);

这篇关于在 ML(SMLNJ) 中打开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！