英文:
using jq how can i change the value of a key?
问题
使用jq如何更改键的值？
我试图根据键的长度来更改键的值。但它似乎没有按预期工作。
echo '[{"kiwi": 3 }, {"apple" : 4} ]' | jq 'map(with_entries(.key |= "\(.)", .value |= (. | length)))'
实际输出：
[
{
"kiwi": 3
},
{
"apple": 4
}
]
期望输出 -
[
{
"kiwi": 4
},
{
"apple": 5
}
]
英文:
Using jq how can i change the value of a key?
I am trying to change the value of a key based on the length of the key. But it seems to not work as expected.
echo '[{"kiwi": 3 }, {"apple" : 4} ]' | jq 'map(with_entries(.key |= "\(.)", .value |= (. | length)))'
actual output:
[
{
"kiwi": 3
},
{
"apple": 4
}
]
desired output -
[
{
"kiwi": 4
},
{
"apple": 5
}
]
答案1
得分: 4
在 with_entries 内部，只需要使用 = 将计算得到的值（.key | length）分配给 .value。.key 的值保持不变。
map(with_entries(.value = (.key | length)))
[
{
"kiwi": 4
},
{
"apple": 5
}
]
英文:
Within with_entries, you only need to assign the computed value (.key | length) to .value using =. The value of .key remains unaltered.
map(with_entries(.value = (.key | length)))
[
{
"kiwi": 4
},
{
"apple": 5
}
]
答案2
得分: 3
你想要
```jq
map( with_entries( .value = ( .key | length ) ) )
解释如下。
.value |= ( . | length )
大致等同于
.value = ( .value | . | length )
所以你实际上是在执行 3 | length 和 4 | length。当给定一个数字时，length 会产生这个数字。所以这些分别产生 3 和 4。
你想要的是键的长度。
.value = ( .key | length )
同样地，
.key |= "\(.)"
可以看作
.key = ( .key | "\(.)" )
由于键已经是一个字符串，这实际上是
.key = .key
这实际上什么都不做。```
英文:
You want
map( with_entries( .value = ( .key | length ) ) )
Explanation follows.
.value |= ( . | length )
is roughly equivalent to
.value = ( .value | . | length )
So you are effectively doing 3 | length and 4 | length. When given a number, length produces the number. So these produce 3 and 4 respectively.
You want the length of the key.
.value = ( .key | length )
Similarly,
.key |= "\(.)"
can be seen as
.key = ( .key | "\(.)" )
Since the key is already a string, that's just
.key = .key
And this does nothing at all.
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