Question

我有一堆文件比字段名称有更多的值（不必要的值），而且我还有一个我希望保留的标题。

例如，使用包含以下内容的test_awk.txt文件

My header is here
it can have several lines
data1 data2 data3
1,2,3,4
2,3,4,5

我想要的是以下内容：

My header is here
it can have several lines
data1,data2,data3
1,2,3
2,3,4

我尝试使用简单的awk命令，但只能抑制整个文件的列。因此，删除我的标题，最重要的是，删除最后一个字段名称：

awk 'BEGIN{FS=OFS=","}NR>2{NF--;print}' test_awk.txt

给出：

data1,data2
1,2,3
2,3,4

Answer 1

关注awk可能对您有帮助。

awk -F' |,' '/^data/{val=NF;} /^[0-9]/ && NF>val{NF=val} 1' OFS=,   Input_file

输出如下。

My header is here
it can have several lines
data1 data2 data3
1,2,3
2,3,4

说明： 此处还添加了非单一的班轮表格，并附上说明：

awk -F' |,' '         ##Making field separator as space or comma for each line of Input_file here.
/^data/{              ##Checking condition here if a line is starting from string data, if yes then do following:
  val=NF;             ##Creating variable named val and its value is value of the number of fields on current line of Input_file.
}
/^[0-9]/ && NF>val{   ##Checking condition here if any line starts from digits and value of current NF is greater than variable val then do following:
  NF=val              ##Assigning the value of NF to variable named val here.
}
1                     ##Mentioning 1 here will make sure I we are making condition TRUE here and not mentioning any action here so by default print of current line will happen as an action.
' OFS=, Input_file    ##Setting OFS(output field separator) as comma here and mentioning Input_file here.

Answer 2

$ awk 'BEGIN{FS=OFS=","} NR>3{NF--} 1' test_awk.txt My header is here it can have several lines data1 data2 data3 1,2,3 2,3,4表示如果NR> 3，则更改NF并打印..所以这会错过打印行NR＆lt; = 3

NR>3{NF--}

1仅更改行号的字段数＆gt; 3
$0以惯用方式打印sed

您也可以使用$ sed '4,$ s/,[^,]*$//' test_awk.txt My header is here it can have several lines data1 data2 data3 1,2,3 2,3,4

4,$

s/,[^,]*$//替换仅适用于这些行 - 即行号＆gt; 3
#include<iostream> using namespace std; int main() { cout<<"HELLOW WORLD"; return 0; }删除最后一个字段

删除字段，使用命令行保留标题

2 个答案: