![]() # list the values of the tags which names are "Name"Īws ec2 describe-vpcs | jq -r '.|. Or with an aws cli command # list my vpcs or # this ^^^ MUST start first on the line - no whitespace there !!! If to_entries is passed an object, then for each k: v entry in These functions convert between an object and an array of key-value Jq provides to_entries and from_entries to convert between objects and key-value pair arrays. extract references are used to populate the two new keys.I had a similar related question: What if you wanted the original object format back (with key names, e.g. Next, we iterate over this array and for each item create an object containing the two keys page_title and page_description.Then we iterate over this array and pass each object inside the pages array to the map function, where we simply create a new array with the contents of each object. ![]() First, we begin by accessing the pages array and passing that array into the next filter in the command via a pipe.We’ll take a look at the command in more detail to understand it properly: In this example, we’ll use some Wikipedia JSON that describes a list of page entries: ]' wikipedia.json This can be useful while working with large JSON structures when we are only interested in several properties or values. This means we will start two indexes from the end (-2), and since the second argument is empty, it will run until the end of the array.įrequently when working with data structures such as JSON, we might want to transform one data structure into another. Note the subtle difference in the second slice - we pass the index as the first argument. The second slicing operation has a negative argument, which denotes in this case that it counts backward from the end of the array. , the slice will start from the beginning of the array and run up until index 6. Since we specified only the second argument in. It’s also possible to omit one of the indexes when using the slicing functionality: echo '' | jq '.' | jq '.' The result will be a new array with a length of 3, containing the elements from index 6 (inclusive) to index 9 (exclusive): [ This is particularly useful when we need to return a subarray of an array.Īgain, let’s see this using a simple array of numbers: echo '' | jq '.' Accessing by Indexįinally, jq also supports slicing of arrays, another powerful feature. We can also use a slightly more concise version and access the property directly on each object in the array: jq '.name' fruits.json 4.2. The last step is to output the name field from each object using. Then we can pass each object in the array to the next filter in the command using a pipe |. name' fruits.jsonįirst, we iterate over the array using. Let’s see how to extract the name of each fruit from each object in the array: jq '. Now let’s imagine we want to represent a list of fruit in a JSON document: [Įach item in the array is an object that represents a fruit. in use, which will print out each item in the array on a separate line: "x" jq is useful to slice, filter, map and transform structured json data. jq (JSON Query utility for Bash CLI scripts) Define JMESPATH syntax in query Extract city and other data from IP address lookup website ipinfo.io, Docker Hub, and other sites NOTE: Content here are my personal opinions, and not intended to represent any employer (past or present). Here, we see the object value iterator operator. We’ll start with a basic example to demonstrate how to iterate over an array: echo '' | jq '.'
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