Concatenates the values of all fields with the same name and an array suffix into a value in a new field. Such array fields typically come as output from either parseJson() or splitString().

All array fields starting with index from and ending with index to are selected. If some index is missing, the concatenation stops with the previous index, thus if only index 0, 1 and 3 are present, only index 0 and 1 are concatenated. If the first index is missing, no field is added to the event.

ParameterTypeRequiredDefault ValueDescription
asstringoptional[a]_concatArray Name of output field.
field[b]stringrequired  Base name for array fields to concatenate.
fromnumberoptional[a]0 First array index to include [0..∞].
prefixstringoptional[a]  Prefix to prepend to the generated string.
separatorstringoptional[a]  Separator between values.
suffixstringoptional[a]  Suffix to append to the generated string.
tonumberoptional[a]  Last array index to include (leave out to get all). Must be equal to or larger than from.

[a] Optional parameters use their default value unless explicitly set.

[b] The argument name field can be omitted.

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Show omitted argument names for this function

concatArray() Examples

Concatenate Object Arrays Into Single Array

Query
logscale
"a[0].foo" := "a" 
| "a[0].bar" := "b" 
| "a[1].foo" := "c" 
| "a[1].bar" := "d"
        
| objectArray:eval(array="a[]", asArray="output[]", var="x", function={output := x.bar})
| concatArray("output")
Introduction

The objectArray:eval() function is a structured array query function that follows normal array syntax. The array syntax is similar to the one used by JSON, where [ and ] are used for indexing and . for selecting members in objects. For more information, see Array Syntax. The objectArray:eval() function operates on arrays of objects. In this example, the objectArray:eval() function is used to extract one object from each element of an array of objects and then uses concatArray() to create a single string of the values.

Example incoming data might look like this:

Raw Events
a[0].foo: a
a[0].bar: b
a[1].foo: c
a[1].bar: d

Step-by-Step

  1. Starting with the source repository events

  2. logscale
    "a[0].foo" := "a" 
| "a[0].bar" := "b" 
| "a[1].foo" := "c" 
| "a[1].bar" := "d"

  3. logscale
    | objectArray:eval(array="a[]", asArray="output[]", var="x", function={output := x.bar})

    Iterates (creates a loop) over the array a[] and adds the value of the object .bar to a new array output[]. This is achieved by executing an anonymous function, which sets the value of output to the iterated value of x.bar from a[].

    The asArray parameter is set to the output[] field, and then when we assign the value of x.bar to this output[] field.

  4. logscale
    | concatArray("output")

    Concatenates the array values in the output array and returns the result in a new field named _concatArray.

    Notice that the concatArray() function concatenates the elements of the supplied array and returns a string, containing the joined arrays. The concatArray() method does not change the existing arrays.

  5. Event Result set

Summary and Results

The query is used to create a single value from compound arrays. This can be useful when you need to generate an identity field from a nested array, for example when summarizing data, or to create compound values from class definitions or IP addresses.

Sample output from the incoming example data:

a[0].fooa[0].bara[1].fooa[1].baroutput[0]output[1]_concatArray
abcdbdbd

Concatenate Values from Deeply Nested Array Elements - Example 3

Query
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objectArray:eval(
        "in[]", 
        asArray="out[]", 
        function={
objectArray:eval("in.others[]", asArray="tmp[]", function={tmp := "in.others.d"}
          
| out := concatArray(tmp)
          }
          )
Introduction

The objectArray:eval() function is a structured array query function that follows normal array syntax. The array syntax is similar to the one used by JSON, where [ and ] are used for indexing and . for selecting members in objects. For more information, see Array Syntax. The objectArray:eval() function operates on arrays of objects using a function that supports a special pattern to access sub-selections of array entries.

The special pattern that allows the function to operate on arrays of objects, and arrays of arrays, and other arrays of structured data is: "in" (the input array) followed by: 

.subselection

or 

[number]

or any combination of the above. For example: 

in.key, 
in.others[0].foo
in[0][1]

Semantically, given the input array in, an array index i, and an access in.subselection this will be translated to the field name in[i].subselection. Similarly, in[2] is translated to in[i][2].

The objectArray:eval function can be combined with other array functions (or itself), in order to support processing nested arrays.

In this example, the objectArray:eval() function is used with itself to concatenate a deeply nested arrays of objects values in the array in[] and return the concatenated values in the output field out[].

Example incoming data might look like this:

JSON
in[0].others[0].d: 1
in[0].others[1].d: 2
in[0].others[2].d: 3
in[1].others[0].d: 4
in[1].others[1].d: 5
in[1].others[2].d: 6
Step-by-Step

  1. Starting with the source repository events

  2. logscale
    objectArray:eval(
        "in[]", 
        asArray="out[]", 
        function={

    Iterates over the array from start to end (or to the first empty index in the array, applies the given function, and returns the concatenated results in a new output array name field out[].

  3. logscale
    objectArray:eval("in.others[]", asArray="tmp[]", function={tmp := "in.others.d"}
          
| out := concatArray(tmp)
          }
          )

    The nested objectArray:eval() performs the concatenation of the values within the nested array by calling the concatArray() function.

    Notice that in the nested call to objectArray:eval(), the given input array name is the nested array in.others[]. This works because it is translated to the field in[i].others[] by the parent objectArray:eval() current array index i.

    To return the concatenated array, the asArray parameter is set to the tmp[] field, and then when we assign the value of the concatenated value.

  4. Event Result set

Summary and Results

The query is used to concatenate deeply nested arrays of objects. The use of this function in this way is often useful when incoming ingested data has been defined in a nested structure, but needs to be displayed or summarized. For example, importing the properties or configuration values may result in a list of potential values for a given property. Concatenating the values together makes them easier to use as a summary value for display in a table or graph.

Sample output from the incoming example data: 

out[0]: 123
out[1]: 456

Concatenate Values in Arrays into New Named Field - Example 2

Query
logscale
concatArray("email", as=servers)
Introduction

The concatArray() method concatenates (joins) two or more arrays and returns a new array, containing the joined arrays. The concatArray() method does not change the existing arrays. For more information, see Array Syntax. In this example, the concatArray() function concatenates the values of all fields with the same name into a value in a new defined field.

Example incoming data might look like this: 

email[0] := "dopey"
email[1] := "sleepy"
email[2] := "doc"
email[3] := "happy"
email[4] := "sneezy"

Step-by-Step

  1. Starting with the source repository events

  2. logscale
    concatArray("email", as=servers)

    Concatenates the values of fields email[0], email[1] and so on and returns the results in a field named servers.

  3. Event Result set

Summary and Results

The query is used to concatenate (join) two or more arrays into a new array. Concatenation is useful in programming and computing because it allows you to store and combine multiple pieces of data when needed.

Sample output from the incoming example data:

email[0]email[1]email[2]email[3]email[4]servers
dopeysleepydochappysneezydopeysleepydochappysneezy

Concatenate Values in Arrays using Pipe Separation

Query
logscale
concatArray(server, separator=" | ")
Introduction

The concatArray() method concatenates (joins) two or more arrays and returns a new array, containing the joined arrays. The concatArray() method does not change the existing arrays. For more information, see Array Syntax. In this example, the concatArray() function concatenates the values of all fields with the same name into pipe separated values in a new field.

Example incoming data might look like this: 

server[0] := "dopey"
server[1] := "sleepy"
server[2] := "doc"
server[3] := "happy"
server[4] := "sneezy"
Step-by-Step

  1. Starting with the source repository events

  2. logscale
    concatArray(server, separator=" | ")

    Concatenates the values of fields server[0], server[1] and so on and returns the results in a new array with a field named _concatArray where the concatenated values are separated by a pipe.

  3. Event Result set

Summary and Results

The query is used to concatenate (join) two or more arrays into a new array where the concatenated values are separated by a pipe. Concatenation is useful in programming and computing because it allows you to store and combine multiple pieces of data when needed.

Sample output from the incoming example data:

server[0]server[1]server[2]server[3]server[4]_concatArray
dopeysleepydochappysneezydopey | sleepy | doc | happy | dopey

Concatenate Values in Arrays with a Defined Prefix and Suffix

Query
logscale
concatArray(server, prefix="[", separator=",", suffix="]")
Introduction

The concatArray() method concatenates (joins) two or more arrays and returns a new array, containing the joined arrays. The concatArray() method does not change the existing arrays. For more information, see Array Syntax. In this example, the concatArray() function concatenates the values of all fields with the same name and an array suffix into a value in a new field, adding a prefix and a suffix to the generated output result.

Example incoming data might look like this: 

server[0] := "dopey"
server[1] := "sleepy"
server[2] := "doc"
server[3] := "happy"
server[4] := "sneezy"

Step-by-Step

  1. Starting with the source repository events

  2. logscale
    concatArray(server, prefix="[", separator=",", suffix="]")

    Concatenates the values of fields server[0], server[1] and so on and returns the results as a string named _concatArray enclosed in square brackets, and separated by a comma, which is similar to the written array format.

  3. Event Result set

Summary and Results

This can be useful to summarize or format a list of items for use in another part of the query.

Sample output from the incoming example data:

server[0]server[1]server[2]server[3]server[4]_concatArray
dopeysleepydochappysneezy[dopey,sleepy,doc,happy,dopey]

Concatenate Values of All Fields with Same Name in an Array - Example 1

Query
logscale
concatArray(server)
Introduction

The concatArray() function concatenates (joins) two or more arrays and returns a new array, containing the joined arrays. The concatArray() method does not change the existing arrays. For more information, see Array Syntax. In this example, the concatArray() function concatenates the values of all fields with the same name into a value in a new field.

Example incoming data might look like this:

Raw Events
server[0] := "dopey"
server[1] := "sleepy"
server[2] := "doc"
server[3] := "happy"
server[4] := "sneezy"
Step-by-Step

  1. Starting with the source repository events

  2. logscale
    concatArray(server)

    Concatenates the values of fields server[0], server[1] and so on and returns the results in a new array with a field named _concatArray. If no field is defined, the aggregate function always creates a field name beginning with underscore for the returned values.

  3. Event Result set

Summary and Results

The query is used to concatenate (join) two or more arrays into a new array. Concatenation is useful in programming and computing because it allows you to store and combine multiple pieces of data when needed.

Sample output from the incoming example data:

_concatArray: dopeysleepydochappysneezy
server [0]
server [1]
server [2]
server [3]
server [4]

Concatenate a Range of Values in Arrays - Example 3

Query
logscale
concatArray(server, from=1, to=3)
Introduction

The concatArray() method concatenates (joins) two or more arrays and returns a new array, containing the joined arrays. The concatArray() method does not change the existing arrays. For more information, see Array Syntax. In this example, the concatArray() function concatenates the values of all fields with the same name and index between 1 to 3 into a value in a new field.

Example incoming data might look like this: 

server[0] := "dopey"
server[1] := "sleepy"
server[2] := "doc"
server[3] := "happy"
server[4] := "sneezy"

Step-by-Step

  1. Starting with the source repository events

  2. logscale
    concatArray(server, from=1, to=3)

    Concatenates the values of fields server[1], server[2], and server[3], and returns the results in a new array with a field named _concatArray.

  3. Event Result set

Summary and Results

The query is used to concatenate (join) two or more arrays into a new array. Concatenation is useful in programming and computing because it allows you to store and combine multiple pieces of data when needed.

Sample output from the incoming example data:

server[0]server[1]server[2]server[3]server[4]_concatArray
dopeysleepydochappysneezysleepydochappy