如何使用awk检测嵌入的字段名称并重新排序字段? [英] How do I detect embbeded field names and reorder fields using awk?

问题描述

我有以下数据:

"b":1.14105,"a":1.14106,"x":48,"t":1594771200000
"a":1.141,"b":1.14099,"x":48,"t":1594771206000
...

我试图以给定的顺序显示数据，并且仅显示三个字段.由于不能保证字段顺序，因此我需要阅读"tag"标签.每行的每个逗号分隔列.

I am trying to display data in a given order and only for three fields. As the fields order is not guaranteed, I need to read the "tag" for each comma separated column for each line.

我尝试使用awk解决此任务:

I have tried to solve this task using awk:

awk -F',' '
                {
                        for(i=1; i<=$NF; i++) {
                                if(index($i,"\"a\":")!=0) a=$i;
                                if(index($i,"\"b\":")!=0) b=$i;
                                if(index($i,"\"t\":")!=0) t=$i;
                        }
                        printf("%s,%s,%s\n",a,b,t);
                }
        '

但是我得到了

,,
,,
...

在上述数据示例中，我期望:

In the above data sample, I would expect:

"a":1.14106,"b":1.14105,"t":1594771200000
"a":1.141,"b":1.14099,"t":1594771206000
...

注意:我正在使用FreeBSD随附的awk

Note: I am using the awk shipped with FreeBSD

推荐答案

带有awk和一个数组:

awk -F '[:,]' '{for(i=1; i<=NF; i=i+2){a[$i]=$(i+1)}; print "\"a\":" a["\"a\""] ",\"b\":" a["\"b\""] ",\"t\":" a["\"t\""]}' file

或

awk -F '[":,]' '{for(i=2; i<=NF; i=i+4){a[$i]=$(i+2)}; print "\"a\":" a["a"] ",\"b\":" a["b"] ",\"t\":" a["t"]}' file

输出:

"a":1.14106,"b":1.14105,"t":1594771200000
"a":1.141,"b":1.14099,"t":1594771206000

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