计数gnuplot中的csv中的列 [英] Count columns in csv in gnuplot

问题描述

gnuplot中是否有一个函数可以返回csv文件中的列数? 我在文档中找不到任何内容，也许有人可以为此建议自定义功能?

Is there a function in gnuplot which returns the number of columns in a csv file? I can't find anything in the docs, maybe someone can propose a custom made function for this?

推荐答案

从gnuplot4.6开始，您可以编写一些hack脚本来执行此操作.它当然不是最有效的，但它是纯gnuplot:

As of gnuplot4.6, you can make a little hack script to do this. It is certainly not the most efficient, but it is pure gnuplot:

#script col_counter.gp
col_count=1
good_data=1
while (good_data){
   stats "$0" u (valid(col_count))
   if ( STATS_max ){
      col_count = col_count+1
   } else {
      col_count = col_count-1
      good_data = 0
   }
}

现在在您的主脚本中，

call "col_counter.gp" "my_datafile_name"
print col_count   #number of columns is stored in col_count.

这有一些局限性-如果数据文件中的一列完全是非数字的，然后再加上更有效的列，这将使您感到窒息，但是我认为它应该适用于许多典型的用例.

This has some limitations -- It will choke if you have a column in the datafile that is completely non-numeric followed by more valid columns for example, but I think that it should work for many typical use cases.

print col_count

最后，您可以使用环境变量GNUPLOT_LIB，然后甚至不需要在当前目录中使用col_counter.gp.

As a final note, you can use the environment variable GNUPLOT_LIB and then you don't even need to have col_counter.gp in the current directory.

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