在 Tcl 脚本中转换列表中的列 [英] Converting Columns in a List in Tcl Script

问题描述

我想使用 Tcl 脚本将文件的一列转换为列表.我有一个文件名input.dat"，其中包含两列数据，如下所示:

I want to convert a column of a file in to list using Tcl Script. I have a file names "input.dat" with the data in two columns as follows:

7 0

9 9

0 2

2 1

3 4

我想将第一列转换成一个列表，我编写了如下的 Tcl 脚本:

And I want to convert the first column into a list and I wrote the Tcl Script as follows:

set input [open "input.dat" r]
set data [read $input]
set values [list]
foreach line [split $data \n] {

  lappend values [lindex [split $line " "] 0]
}

puts "$values"
close $input

结果显示为:7 9 0 2 3 {} {}

The result shows as: 7 9 0 2 3 {} {}

现在，我的问题是这两个额外的{}"是什么，我的脚本中的错误是什么，因为它产生了两个额外的{}"，我该如何解决这个问题?

Now, my question is what is these two extra "{}" and what is the error in my script because of that it's producing two extra "{}" and How can I solve this problem?

有人可以帮我吗?

推荐答案

除非间歇性空字符串对您的程序任务具有重要意义，否则您还可以使用从 Tcl 列表(带有空字符串元素)到字符串的转换修剪空字符串元素(在末端和中间):

Unless intermittent empty strings carry some meaning important to your program's task, you may also use a transformation from a Tcl list (with empty-string elements) to a string that prunes empty-string elements (at the ends, and in-between):

concat {*}[split $data "\n"]

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