assume I have a string
假设我有一个字符串
"1,2,3,4"
Now I want to replace, e.g. the 3rd field of the string by some different value.
现在我想替换，例如字符串的第3个字段由一些不同的值组成。
"1,2,NEW,4"
I managed to do this with the following command:
我设法使用以下命令执行此操作：
echo "1,2,3,4" | awk -F, -v OFS=, '{$3="NEW"; print }'
Now the index for the column to be replaced should be passed as a variable. So in this case
现在要替换的列的索引应该作为变量传递。所以在这种情况下
index=3
How can I pass this to awk? Because this won't work:
我怎么能把这个传递给awk？因为这不起作用：
echo "1,2,3,4" | awk -F, -v OFS=, '{$index="NEW"; print }'
echo "1,2,3,4" | awk -F, -v OFS=, '{$($index)="NEW"; print }'
echo "1,2,3,4" | awk -F, -v OFS=, '{\$$index="NEW"; print }'
Thanks for your help!
谢谢你的帮助！
5 个解决方案
#1
6
Have the shell interpolate the index in the awk program:
让shell在awk程序中插入索引：
echo "1,2,3,4" | awk -F, -v OFS=, '{$'$index'="NEW"; print }'
Note how the originally single quoted awk program is split in three parts, a single quoted beginning '{$', the interpolated index value, followed by the single quoted remainder of the program.
请注意原始单引号awk程序如何分为三部分，单引号开头'{$'，插值索引值，后跟程序的单引号余数。
#2
5
This might work for you:
这可能对你有用：
index=3
echo "1,2,3,4" | awk -F, -v OFS=, -v INDEX=$index '{$INDEX="NEW"; print }'
or:
要么：
index=3
echo "1,2,3,4" | sed 's/[^,]*/NEW/'$index
#3
1
Here's a seductive way to break the awkwardness:
这是一种打破尴尬的诱人方式：
$ echo "1,2,3,4" | sed 's/,/\n/g' | sed -e $index's/.*/NEW/'
This is easily extendable to multiple indexes just by adding another -e $newindex's/.*/NEWNEW/'
只需添加另一个-e $ newindex的/.*/ NEWNEW /'，就可以轻松扩展到多个索引
#4
0
# This should be faster than awk or sed.
str="1,2,3,4"
IFS=','
read -a f <<< "$str"
f[2]='NEW'
printf "${f[*]}"
#5
-1
With plain awk (I.E. Not gawk etc) I believe you'll have to use split( string, array, [fieldsep] ); change the array entry of choice and then join them back together with sprintf or similar in a loop.
使用普通的awk（I.E. Not gawk等）我相信你将不得不使用split（string，array，[fieldsep]）;更改选择的数组条目，然后将它们与sprintf或类似的循环连接在一起。
gawk allows you to have a variable as a field name, $index in your example. See here.
gawk允许您在示例中将变量作为字段名称$ index。看这里。
gawk is usually the default awk on Linux, so change your invocation to gawk "script" and see if it works.
gawk通常是Linux上的默认awk，所以将你的调用更改为gawk“script”并查看它是否有效。
#1
6
Have the shell interpolate the index in the awk program:
让shell在awk程序中插入索引：
echo "1,2,3,4" | awk -F, -v OFS=, '{$'$index'="NEW"; print }'
Note how the originally single quoted awk program is split in three parts, a single quoted beginning '{$', the interpolated index value, followed by the single quoted remainder of the program.
请注意原始单引号awk程序如何分为三部分，单引号开头'{$'，插值索引值，后跟程序的单引号余数。
#2
5
This might work for you:
这可能对你有用：
index=3
echo "1,2,3,4" | awk -F, -v OFS=, -v INDEX=$index '{$INDEX="NEW"; print }'
or:
要么：
index=3
echo "1,2,3,4" | sed 's/[^,]*/NEW/'$index
#3
1
Here's a seductive way to break the awkwardness:
这是一种打破尴尬的诱人方式：
$ echo "1,2,3,4" | sed 's/,/\n/g' | sed -e $index's/.*/NEW/'
This is easily extendable to multiple indexes just by adding another -e $newindex's/.*/NEWNEW/'
只需添加另一个-e $ newindex的/.*/ NEWNEW /'，就可以轻松扩展到多个索引
#4
0
# This should be faster than awk or sed.
str="1,2,3,4"
IFS=','
read -a f <<< "$str"
f[2]='NEW'
printf "${f[*]}"
#5
-1
With plain awk (I.E. Not gawk etc) I believe you'll have to use split( string, array, [fieldsep] ); change the array entry of choice and then join them back together with sprintf or similar in a loop.
使用普通的awk（I.E. Not gawk等）我相信你将不得不使用split（string，array，[fieldsep]）;更改选择的数组条目，然后将它们与sprintf或类似的循环连接在一起。
gawk allows you to have a variable as a field name, $index in your example. See here.
gawk允许您在示例中将变量作为字段名称$ index。看这里。
gawk is usually the default awk on Linux, so change your invocation to gawk "script" and see if it works.
gawk通常是Linux上的默认awk，所以将你的调用更改为gawk“script”并查看它是否有效。