I have a given JSON object .
var item = {VENUE_ID: "146", Cost: 0, Impressions: 0, Position: 0, id: 6} ;
I can extract value by item.VENUE_ID ,item.Cost.
How can i use variable to extract value .I want something like it
var keys="VENUE_ID";
item.keys or item[keys];
Solved it we can use following code to set key dynamic and get value item["" + keys+ ""]
For me
item[keys]
works perfectly where keys = "VENUE_ID"
Anyone facing this requirement, try and access the value the aforesaid way, even the OP posted the correct method in his question. I'm not sure why it didn't work for him in the first place.
Related
I have some JSON data in Redshift table of type character varying. An example entry is:
[{"value":["*"], "key":"testData"}, {"value":"["GGG"], key: "differentData"}]
I want to return vales based on keys, how can i do this? I'm attempting to do something like
json_extract_path_text(column, 'value') but unfortunately it errors out. Any ideas?
So the first issue is that your string isn't valid JSON. There are mismatched and missing quotes. I think you mean:
[{"value":["*"], "key":"testData"}, {"value":["GGG"], "key": "differentData"}]
I don't know if this is a data issue or a transcription error but these functions won't work unless the json text is valid.
The next thing to consider is that at the top level this json is an array so you will need to use json_extract_array_element_text() function to pick up an element of the array. For example:
json_extract_array_element_text('json string', 0)
So putting this together we can extract the first "value" with (untested):
json_extract_path_text(
json_extract_array_element_text(
'[{"value":["*"], "key":"testData"}, {"value":["GGG"], "key": "differentData"}]', 0
), 'value'
)
Should return the string ["*"].
I kind of feel stupid for asking this, but haven't been able to find a way to get the key of a JSON value. I know how to retrieve the key if I have an iterator of the object. I also know of operator[].
In my case the key is not a known value, so can't use get(const char *key) or operator[]. Also can't find a getKey() method.
My JSON looks like this:
{Obj_Array: [{"122":{"Member_Array":["241", "642"]}}]}
For the piece of code to parse {"122":{"Member_Array":["241", "642"]}} I want to use get_key()-like function just to retrieve "122" but seems like I have to use an iterator which to me seems to be overkill.
I might have a fundamental lack of understanding of how jsoncpp is representing a JSON file.
First, what you have won't parse in JsonCPP. Keys must always be enclosed in double quotes:
{"Obj_Array": [{"122":{"Member_Array":["241", "642"]}}]}
Assuming that was just an oversight, if we add whitespace and tag the elements:
{
root-> "Obj_Array" : [
elem0-> {
key0-> "122":
val0-> {
key0.1-> "Member_Array" :
val0.1-> [
elem0.1.0-> "241",
elem0.1.1-> "642" ]
}
}
]
}
Assuming you have managed to read your data into a Json::Value (let's call it root), each of the tagged values can be accessed like this:
elem0 = root[0];
val0 = elem0["122"]
val0_1 = val0["Member_Array"];
elem0_1_0 = val0_1[0];
elem0_1_1 = val0_1[1];
You notice that this only retrieves values; the keys were known a priori. This is not unusual; the keys define the schema of the data; you have to know them to directly access the values.
In your question, you state that this is not an option, because the keys are not known. Applying semantic meaning to unknown keys could be challenging, but you already came to the answer. If you want to get the key values, then you do have to iterate over the elements of the enclosing Json::Value.
So, to get to key0, you need something like this (untested):
elem0_members = elem0.getMemberNames();
key0 = elem0_members[0];
This isn't production quality, by any means, but I hope it points in the right direction.
The problem
Each entity owns an id and a json field. That json field simply stores a json list of objects.
Entity{ id, json }
"1, '[{"tag": "Player"}, {"position": {"x": 20, "y": 20}}]'"
The order of those json objects is not always the same and i want to update the json object inside the array where "tag" :"Player". I basically wanna change the tag.
I tried to use json_replace, but it didnt worked because it seems like that function does not accept the $** wildcard. But i cant use $[0] because that json object is not always at the first position. Thats what i tried.
UPDATE entity
SET jsonComponents = JSON_REPLACE(
jsonComponents ,
'$**.tag' ,
'NewTag'
)
WHERE
entity.id = 1
The Question
How are we supposed to modify/remove an json object inside an pure json list, if we dont know where its located at ? How can we modify/remove a json object inside a list regardless of its position inside the list ?
Im actually very glad for any help on this topic, couldnt find anything about it...
The solution
If we dont know the path of the json object we seek to modify... we simply query for the path using json_search
update entity
set jsonComponents = JSON_REPLACE(
jsonComponents,
JSON_UNQUOTE(json_search(jsonComponents, 'one', 'Player')),
'NewTag'
)
where entity.id = 0
Im trying to work out how to append a zero to a specific JSON decoded array value for multiple records stored in a MySQL table according to some conditions.
for example, for table 'menu', column 'params'(text) have records containing JSON decoded arrays of this format:
{"categories":["190"],"singleCatOrdering":"","menu-anchor_title":""}
and column 'id' has a numeric value of 90.
my goal is to add a zero to 'categories' value in menu.params whenever (for example) menu.id is under 100.
for this records the result being
{"categories":["1900"],"singleCatOrdering":"","menu-anchor_title":""}
so im looking for a SQL Query that will search and find the occurrences of "categories": ["999"] in the Database and update the record by adding a zero to the end of the value.
this answer is partially helpful by offering to use mysql-udf-regexp but its referring to REPLACE a value and not UPDATE it.
perhaps the REGEXP_REPLACE? function will do the trick. i have never used this library and am not familiar with it, perhaps there is an easier way to achieve what i need ?
Thanks
If I understand your question correctly, you want code that does something like this:
var data = {
"menu": {
"id": 90,
"params": {
"categories": ["190"],
"singleCatOrdering": "",
"menu-anchor_title": ""
}
}
};
var keys = Object.keys(data);
var columns;
for (var ii = 0, key; key = keys[ii]; ii++) {
value = data[key];
if (value.id < 100) {
value.params.categories[0] += "0";
alert(value.params.categories[0]);
}
}
jsFiddle
However, I am not using a regular expression at all. Perhaps if you reword the question, the necessity of a regex will become clearer.
"divisions":{
"ocd-division/country:us/state:co/place:aurora":{
"name":"Aurora city",
"scope":"citywide",
"officeIds":[
"O0",
"O1"]
}}
I am using Google Civic Information API to get representive information. let's say this is a part of JSON generated by Google and I want to access its elements but the issue is - i cant use "ocd-division/country:us/state:co/place:aurora" as a key, because its dynamically generated by Google.
If I search for some different address like India, the key will be different from "ocd-division/country:us/state:co/place:aurora" to something else(instead of 'us', there would be 'in'), So please suggest the way I should access in this case the value.
Please clarify if you don't understand question or need more clarification.
Parse the json to a hash:
parsed_data = JSON.parse google_data
then either iterate over all divisions:
parsed_data['divisions'].each do |division_key, division_info|
# do something with each division
end
or get only the first one:
division_key, division_info = parsed_data['divisions'].first
Use this if you want parse the key as well:
more_info = division_key.split('/').inject(Hash.new) do |hash, key_part|
if key_part.include? ":"
key, value = key_part.split ":"
hash[key] = value
end
hash
end
Now you can access it via more_info['country']