Question

我的输入文件如下：

apple 6
banana 7
goat 8

我需要输出为

{6,apple},
{7,banana},
{8,goat}

但是，当我按如下所示运行awk时，它正在打印多余的最后一个逗号（，）。如何避免最后一个逗号？

awk '{print "{"$2","$1"},"}' data
{6,apple},
{7,banana},
{8,goat},

更新：

实际上，我需要这样的输出

{6,apple},
{7,banana},
{8,goat}
]

当我跑步

awk '{print "{"$2","$1"},"}' END {print "\t\t]\n}' data

它给了我

{6,apple},
{7,banana},
{8,goat}, 
]

我不需要最后一个逗号...在这种情况下如何避免？

Answer 1

如何使用以下命令行将其管道传输到sed？

awk ... | sed '$ s/,$//'

Answer 2

使用printf并延迟打印逗号：

$ awk '{printf "%s{%s,%s}",(NR==1?"":"," ORS),$2,$1} END{print ORS "]"}' file
{6,apple},
{7,banana},
{8,goat}
]

Answer 3

这是另一种选择

$ awk 'NR==FNR{n=NR; next} {print "{" $2 "," $1 "}" (FNR==n?"\n]":",")}' file{,}

{6,apple},
{7,banana},
{8,goat}
]

Answer 4

只需延迟输出：

awk 'NR>1{print lastline} {lastline="{" $2 "," $1 "},"; } END{print substr(lastline, 1, length(lastline)-1)}' data

每行打印最后一行的输出，在最后一个逗号末尾打印并打印。

Answer 5

Form Responses 9

Answer 6

这是Perl解决方案

/tmp> cat media.txt
apple 6
banana 7
goat 8
/tmp> perl -lne ' s/(\S+) (\d+)/{$2,$1}/g; if(eof) { print "$_\n]" } else { print "$_," } ' media.txt
{6,apple},
{7,banana},
{8,goat}
]
/tmp>

或

$ perl -lne ' s/(\S+) (\d+)/{$2,$1}/g; print eof ? "$_\n]" : "$_," ' media.txt
{6,apple},
{7,banana},
{8,goat}
]

如果文件可以容纳到内存中，则下面的Perl解决方案将起作用

/tmp> perl -0777 -ne ' s/(\S+) (\d+)/{$2,$1}/g ; print join(",\n",split)."\n]\n" ' media.txt
{6,apple},
{7,banana},
{8,goat}
]
/tmp>

用awk更改最后一个记录分隔符

6 个答案: