Question

因此我的目录中有三个.json文件。我已经动态创建了第一个文件（使用linux bash和jq），其中包含一个对象，包括数组“RATIO”：

ratio.json：

[
 {...,"RATIO":[0.5,0.7,0.8,0.9], ....}
]

在第二个文件中我存储了常量（这只是硬编码所以常量也可以直接移动到代码中，如果这更容易）：

constants.json：

[
 {"ID":"aaa","CONST":250},
 {"ID":"bbb","CONST":350},
 {"ID":"ccc","CONST":200},
 {"ID":"ddd","CONST":190}
]

第三个文件是应该发生“神奇”的地方：

data.json：

[
 {"ID":"aaa","time_CET":"00:00:00"},
 {"ID":"aaa","time_CET":"00:15:00"},
 {"ID":"aaa","time_CET":"00:30:00"},
 {"ID":"aaa","time_CET":"00:45:00"},

 {"ID":"bbb","time_CET":"00:00:00"},
 {"ID":"bbb","time_CET":"00:15:00"},
 {"ID":"bbb","time_CET":"00:30:00"},
 {"ID":"bbb","time_CET":"00:45:00"},

 {"ID":"ccc","time_CET":"00:00:00"},
 {"ID":"ccc","time_CET":"00:15:00"},
 {"ID":"ccc","time_CET":"00:30:00"},
 {"ID":"ccc","time_CET":"00:45:00"},

 {"ID":"ddd","time_CET":"00:00:00"},
 {"ID":"ddd","time_CET":"00:15:00"},
 {"ID":"ddd","time_CET":"00:30:00"},
 {"ID":"ddd","time_CET":"00:45:00"}
]

此数组中的所有对象都应该通过元素“VAL”进行扩展，该元素是通过将RATIO与CONST相乘来计算的。所以在我的情况下，RATIO [0]（即0.5）用于time_CET =“00:00:00”的每个对象。 RATIO [1]用于time_CET = 00:15:00等，依此类推。 data.json中的数组已经按照您所看到的排序（00:00:00总是每个ID的第一个），这就是为什么我认为数组索引的技巧应该有效。所以最后，data.json文件看起来应该是这样的（右边是VAL的计算逻辑）：

data.json：

[     

  {"ID":"aaa","time_CET":"00:00:00", "VAL": 125}, ->0.5*250
  {"ID":"aaa","time_CET":"00:15:00", "VAL": 175}, ->0.7*250
  {"ID":"aaa","time_CET":"00:30:00", "VAL": 200}, ->0.8*250
  {"ID":"aaa","time_CET":"00:45:00", "VAL": 225}, ->0.9*250

  {"ID":"bbb","time_CET":"00:00:00", "VAL": 175}, ->0.5*350
  {"ID":"bbb","time_CET":"00:15:00", "VAL": 245}, ->0.7*350
  {"ID":"bbb","time_CET":"00:30:00", "VAL": 280}, ->0.8*350
  {"ID":"bbb","time_CET":"00:45:00", "VAL": 315}, ->0.9*350

  {"ID":"ccc","time_CET":"00:00:00", "VAL": 100}, ->0.5*200
  {"ID":"ccc","time_CET":"00:15:00", "VAL": 140}, ->0.7*200
  {"ID":"ccc","time_CET":"00:30:00", "VAL": 160}, ->0.8*200
  {"ID":"ccc","time_CET":"00:45:00", "VAL": 180}, ->0.9*200

  {"ID":"ddd","time_CET":"00:00:00", "VAL": 95}, ->0.5*190
  {"ID":"ddd","time_CET":"00:15:00", "VAL": 133}, ->0.7*190
  {"ID":"ddd","time_CET":"00:30:00", "VAL": 152}, ->0.8*190
  {"ID":"ddd","time_CET":"00:45:00", "VAL": 171}, ->0.9*190
]

所以我不确定这是否可行。也许我必须将比率数组重塑为对象？（具有“time_cet”键且不是值数组的对象）。

无论如何，使用jq（也许是linux bash）实现这一目标的最佳方法是什么？谢谢！

更新：两种解决方案现在都有效，非常感谢。这可能是另一个主题，但我想添加一个错误处理程序来捕获异常，特别是对于RATIO数组。可能会发生这个数组

1.不包含指定索引/未定义的值

2.Value不是整数

无论如何我想为VAL设置一个默认值。错误消息应该记录在另一个文件中，如果可能的话..（我可以在这里使用当前日期吗？ - ＆gt;也许可以发送到STDERR？）Thx。

Answer 1

假设以下jq程序在一个文件中，比如program.jq，那么调用：

jq --argfile ratio ratio.json --argfile constants constants.json  -f program.jq data.json

产生所需的结果，至少在使用jq 1.5或更高版本时：

# r should be an array of ratios
# input is assumed to be an object with .time_CET
def getRatio(r):
  if .time_CET=="00:00:00" then r[0]
  elif  .time_CET=="00:15:00" then r[1]
  elif  .time_CET=="00:30:00" then r[2]
  else r[3]
  end
  ;

def todict: reduce .[] as $o ({}; . + ($o | { (.ID): .CONST }));

def extend(r):
  ($constants|todict)[.ID]  as $c
  | .VAL = getRatio(r) * $c
  ;

($ratio[0] | .RATIO) as $RATIO
| map(extend($RATIO))

Answer 2

这是一个解决方案：

# recent versions of jq include this in builtin.jq.
# we redefine it here in case it's not present
def INDEX(stream; idx_expr):
  reduce stream as $row (
    {}
  ; .[$row|idx_expr|if type != "string" then tojson else . end] |= $row
  )
;

# make an array of all the times that appear in time_CET
def datatimes:
   [$data[].time_CET] | unique[]
;

# make an object mapping time_CET to ratios
def time_to_ratio:
    reduce datatimes as $i (
      {}
    ; .[$i] = $ratio[0].RATIO[length]
    )
;

# main procedure here

  INDEX($constants[];.ID) as $ctable
| time_to_ratio as $rtable
| $data
| map(.VAL = $ctable[.ID].CONST * $rtable[.time_CET])

如果此过滤器位于filter.jq且其他数据分别位于constants.json，ratio.json和data.json文件中，则命令

jq -Mnc \
   --argfile constants constants.json \
   --argfile data data.json \
   --argfile ratio ratio.json \
   -f filter.jq

产生

[
  {
    "ID": "aaa",
    "time_CET": "00:00:00",
    "VAL": 125
  },
  {
    "ID": "aaa",
    "time_CET": "00:15:00",
    "VAL": 175
  },
  {
    "ID": "aaa",
    "time_CET": "00:30:00",
    "VAL": 200
  },
  {
    "ID": "aaa",
    "time_CET": "00:45:00",
    "VAL": 225
  },
  {
    "ID": "bbb",
    "time_CET": "00:00:00",
    "VAL": 175
  },
  {
    "ID": "bbb",
    "time_CET": "00:15:00",
    "VAL": 244.99999999999997
  },
  {
    "ID": "bbb",
    "time_CET": "00:30:00",
    "VAL": 280
  },
  {
    "ID": "bbb",
    "time_CET": "00:45:00",
    "VAL": 315
  },
  {
    "ID": "ccc",
    "time_CET": "00:00:00",
    "VAL": 100
  },
  {
    "ID": "ccc",
    "time_CET": "00:15:00",
    "VAL": 140
  },
  {
    "ID": "ccc",
    "time_CET": "00:30:00",
    "VAL": 160
  },
  {
    "ID": "ccc",
    "time_CET": "00:45:00",
    "VAL": 180
  },
  {
    "ID": "ddd",
    "time_CET": "00:00:00",
    "VAL": 95
  },
  {
    "ID": "ddd",
    "time_CET": "00:15:00",
    "VAL": 133
  },
  {
    "ID": "ddd",
    "time_CET": "00:30:00",
    "VAL": 152
  },
  {
    "ID": "ddd",
    "time_CET": "00:45:00",
    "VAL": 171
  }
]

jq：将数组中的值与常量相乘，并将结果添加到另一个文件中具有匹配id的对象

2 个答案: