单个空间作为带awk的字段分隔符 [英] single space as field separator with awk

问题描述

我正在处理一个文件，其中字段由单个空格分隔.

I am dealing with a file where fields are separated by a single space.

awk将FS " "解释为一个或多个空格"，当其中一个字段为空时，它将错误读取我的文件.

awk interprets the FS " " as "one or more whitespace", which misreads my file when one of the fields is empty.

我尝试使用空格后不加空格"(" (?! )")作为FS，但是awk不支持否定的超前.简单的Google查询(例如单个空格分隔符awk")仅将我带到手册页，解释了FS=" "的特殊处理.我一定错过了相关的手册页...

I tried using "a space not followed by a space"( " (?! )" ) as FS but awk does not support negative lookahead. Simple google queries like "single space field separator awk" only sent me to the manual page explaining the special treatment of FS=" ". I must have missed the relevant manual page...

如何在awk中使用单个空格作为字段分隔符?

How can I use a single space as field separator with awk?

推荐答案

这应该有效

$ echo 'a    b' | awk -F'[ ]' '{print NF}'
5

其中，这会将所有连续的空白都视为一个空白.

where as, this treats all contiguous white space as one.

$ echo 'a    b' | awk -F' ' '{print NF}'
2

基于注释，需要特别考虑，空字符串或空格，因为字段值是非常不同的东西，可能与空格分隔的内容不太匹配.

based on the comment, it need special consideration, empty string or white space as field value are very different things probably not a good match for a white space separated content.

例如，建议使用cut进行预处理并更改定界符

I would suggest preprocessing with cut and changing the delimiters, for example

$ echo 'a    b' | cut -d' ' -f1,3,5 --output-delimiter=,
a,,b

这篇关于单个空间作为带awk的字段分隔符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！