[英]How to use a regex for the field separator in AWK?
I read another answer that show how one can set the field separator using the -F
flag: 我读了另一个答案 ,显示了如何使用-F
标志设置字段分隔符:
awk -F 'INFORMATION DATA ' '{print $2}' t
Now I'm curious how I can use a regex for the field separator. 现在,我很好奇如何将正则表达式用于字段分隔符。 My attempt can be seen below: 我的尝试可以在下面看到:
$ echo "1 2 foo\n2 3 bar\n42 2 baz"
1 2 foo
2 3 bar
42 2 baz
$ echo "1 2 foo\n2 3 bar\n42 2 baz" | awk -F '\d+ \d+ ' '{ print $2 }'
# 3 blank lines
I was expecting to get the following output: 我期望得到以下输出:
foo
bar
baz
This is because my regex \\d+ \\d+
matches "the first 2 numbers separated by a space, followed by a space". 这是因为我的正则表达式\\d+ \\d+
匹配“前两个数字,中间用空格隔开,后跟一个空格”。 But I'm printing the second record. 但是我正在打印第二条记录。 As shown on rubular : 如图所示上rubular :
Just replace \\d
with [0-9]
: 只需将\\d
替换为[0-9]
:
With this you can print all the fields and you can see the fields immediatelly: 这样,您可以打印所有字段,并且可以立即看到这些字段:
$ echo -e "1 2 foo\n2 3 bar\n42 2 baz" |awk -v FS="[0-9]+ [0-9]+" '{for (k=1;k<=NF;k++) print k,$k}'
1
2 foo
1
2 bar
1
2 baz
So just use [0-9] in your command: 因此,只需在命令中使用[0-9]:
$ echo -e "1 2 foo\n2 3 bar\n42 2 baz" |awk -v FS="[0-9]+ [0-9]+" '{print $2}'
foo
bar
baz
First of all echo
doesn't auto escape and outputs a literal \\n
. 首先, echo
不会自动转义并输出文字\\n
。 So you'll need to add -e
to enable escapes. 因此,您需要添加-e
以启用转义。 Second of all awk
doesn't support \\d
so you have to use [0-9]
or [[:digit:]]
. 第二, awk
不支持\\d
因此您必须使用[0-9]
或[[:digit:]]
。
echo -e "1 2 foo\n2 3 bar\n42 2 baz" | awk -F '[0-9]+ [0-9]+ ' '{ print $2 }'
or 要么
echo -e "1 2 foo\n2 3 bar\n42 2 baz" | awk -F '[[:digit:]]+ [[:digit:]]+ ' '{ print $2 }'
Both outputs: 两个输出:
foo
bar
baz
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