String functions

​

String functions

Each argument has a required section which is denoted with required or optional

• If it’s denoted by required it means the argument must be passed into that function before it’ll work.
• if it’s denoted by optional it means the function can work without passing the argument value.

​

base64_encode_tostring()

Encodes a string as base64 string.

​

Arguments

​

Returns

Returns the string encoded as base64 string.

• To decode base64 strings to UTF-8 strings, see base64_decode_tostring()

​

Examples

base64_encode_tostring(string)

['sample-http-logs']
| project encoded_base64_string = base64_encode_tostring(content_type)

Run in Playground

​

base64_decode_tostring()

Decodes a base64 string to a UTF-8 string.

​

Arguments

​

Returns

Returns UTF-8 string decoded from base64 string.

• To encode strings to base64 string, see base64_encode_tostring()

​

Examples

base64_decode_tostring(string)

['sample-http-logs']
| project decoded_base64_string = base64_decode_tostring("VGhpcyBpcyBhbiBlbmNvZGVkIG1lc3NhZ2Uu")

Run in Playground

​

countof()

Counts occurrences of a substring in a string.

​

Arguments

​

Returns

The number of times that the search string can be matched.

​

Examples

countof(search, text)

['sample-http-logs']
| project count = countof("con", "content_type")

Run in Playground

​

countof_regex()

Counts occurrences of a substring in a string. regex matches don’t.

​

Arguments

• text source: A string.
• regex search: regular expression to match inside your text source.

​

Returns

The number of times that the search string can be matched in the dataset. Regex matches do not.

​

Examples

countof_regex(regex, text)

['sample-http-logs']
| project count = countof_regex("c.n", "content_type")

Run in Playground

​

coalesce()

Evaluates a list of expressions and returns the first non-null (or non-empty for string) expression.

​

Arguments

​

Returns

The value of the first argument whose value isn’t null (or not-empty for string expressions).

​

Examples

['sample-http-logs']
| project coalesced = coalesce(content_type, ['geo.city'], method)

Run in Playground

['http-logs']
| project req_duration_ms, server_datacenter, predicate = coalesce(content_type, method, status)

Run in Playground

​

extract()

Retrieve the first substring matching a regular expression from a source string.

​

Arguments

​

Returns

If regex finds a match in source: the substring matched against the indicated capture group captureGroup, optionally converted to typeLiteral.

If there’s no match, or the type conversion fails: -1 or string error

​

Examples

extract(regex, captureGroup, source)

['sample-http-logs']
| project extract_sub =  extract("^.{2,2}(.{4,4})", 1, content_type)

Run in Playground

extract("x=([0-9.]+)", 1, "axiom x=65.6|po") == "65.6"

Run in Playground

​

extract_all()

Retrieve all substrings matching a regular expression from a source string. Optionally, retrieve only a subset of the matching groups.

​

Arguments

​

Returns

• If regex finds a match in source: Returns dynamic array including all matches against the indicated capture groups captureGroups, or all of capturing groups in the regex.
• If number of captureGroups is 1: The returned array has a single dimension of matched values.
• If number of captureGroups is more than 1: The returned array is a two-dimensional collection of multi-value matches per captureGroups selection, or all capture groups present in the regex if captureGroups is omitted.
• If there’s no match: -1

​

Examples

extract_all(regex, [captureGroups,] source)

['sample-http-logs']
| project extract_match =  extract_all(@"(\w)(\w+)(\w)", dynamic([1,3]), content_type)

Run in Playground

extract_all(@"(\w)(\w+)(\w)", dynamic([1,3]), content_type) == [["t", "t"],["c","v"]]

​

format_bytes()

Formats a number as a string representing data size in bytes.

​

Arguments

​

Returns

• A formatted string for humans

​

Examples

format_bytes( 4000, number, "['id']", num_comments ) == "3.9062500000000 KB"

format_bytes(value [, precision [, units [, base]]])

format_bytes(1024) == "1 KB"

format_bytes(8000000, 2, "MB", 10) == "8.00 MB"

['github-issues-event']
| project formated_bytes =  format_bytes( 4783549035, number, "['id']", num_comments  )

Run in Playground

​

format_url()

Formats an input string into a valid URL. This function will return a string that is a properly formatted URL.

​

Arguments

​

Returns

• A string that represents a properly formatted URL.

​

Examples

['sample-http-logs']
| project formatted_url = format_url(dynamic({"scheme": "https", "host": "github.com", "path": "/axiomhq/next-axiom"})

Run in Playground

['sample-http-logs']
| project formatted_url = format_url(dynamic({"scheme": "https", "host": "github.com", "path": "/axiomhq/next-axiom", "port": 443, "fragment": "axiom","user": "axiom", "password": "apl"}))

Run in Playground

• These are all the supported keys when using the format_url function: scheme, host, port, fragment, user, password, query.

​

indexof()

Reports the zero-based index of the first occurrence of a specified string within the input string.

​

Arguments

​

Returns

• Zero-based index position of lookup.

• Returns -1 if the string isn’t found in the input.

​

Examples

indexof( body, ['id'], 2, 1, number ) == "-1"

indexof(source,lookup[,start_index[,length[,occurrence]]])

indexof ()

['github-issues-event']
| project occurrence = indexof( body, ['id'], 23, 5, number )

Run in Playground

​

isempty()

Returns true if the argument is an empty string or is null.

​

Returns

Indicates whether the argument is an empty string or isnull.

​

Examples

isempty("") == true

isempty([value])

['github-issues-event']
| project empty = isempty(num_comments)

Run in Playground

​

isnotempty()

Returns true if the argument isn’t an empty string, and it isn’t null.

​

Examples

isnotempty("") == false

isnotempty([value])

notempty([value]) -- alias of isnotempty

['github-issues-event']
| project not_empty = isnotempty(num_comments)

Run in Playground

​

isnotnull()

Returns true if the argument is not null.

​

Examples

isnotnull( num_comments ) == true

isnotnull([value])

notnull([value]) - alias for `isnotnull`

['github-issues-event']
| project not_null = isnotnull(num_comments)

Run in Playground

​

isnull()

Evaluates its sole argument and returns a bool value indicating if the argument evaluates to a null value.

​

Returns

True or false, depending on whether or not the value is null.

​

Examples

isnull(Expr)

['github-issues-event']
| project is_null = isnull(creator)

Run in Playground

​

parse_bytes()

Parses a string including byte size units and returns the number of bytes

​

Arguments

​

Returns

• The number of bytes or zero if unable to parse

​

Examples

parse_bytes(bytes_string [, base])

parse_bytes("1 KB") == 1024

parse_bytes("1 KB", 10) == 1000

parse_bytes("128 Bytes") == 128

parse_bytes("bad data") == 0

['github-issues-event']
| extend parsed_bytes =  parse_bytes("300 KB", 10)

Run in Playground

['github-issues-event']
| project parsed_bytes =  parse_bytes("300 KB", 10)

Run in Playground

​

parse_json()

Interprets a string as a JSON value and returns the value as dynamic.

​

Arguments

​

Returns

An object of type json that is determined by the value of json:

• If json is of type string, and is a properly formatted JSON string, then the string is parsed, and the value produced is returned.

• If json is of type string, but it isn’t a properly formatted JSON string, then the returned value is an object of type dynamic that holds the original string value.

​

Examples

parse_json(json)

['vercel']
| extend parsed = parse_json('{"name":"vercel", "statuscode":200, "region": { "route": "usage streams", "number": 9 }}')

['github-issues-event']
| extend parsed = parse_json(creator)
| where isnotnull( parsed)

Run in Playground

​

parse_url()

Parses an absolute URL string and returns an object contains URL parts.

​

Arguments

​

Returns

An object of type dynamic that included the URL components: Scheme, Host, Port, Path, Username, Password, Query Parameters, Fragment.

​

Examples

parse_url(url)

['sample-http-logs']
| extend ParsedURL = parse_url("https://www.example.com/path/to/page?query=example")
| project 
  Scheme = ParsedURL["scheme"],
  Host = ParsedURL["host"],
  Path = ParsedURL["path"],
  Query = ParsedURL["query"]

Run in Playground

• Result

{
  "Host": "www.example.com",
  "Path": "/path/to/page",
  "Query": {
    "query": "example"
  },
  "Scheme": "https"
}

​

parse_urlquery()

Returns a dynamic object contains the Query parameters.

​

Arguments

query: A string represents a url query

​

Returns

An object of type dynamic that includes the query parameters.

​

Examples

parse_urlquery("a1=b1&a2=b2&a3=b3")

Run in Playground

• Result

{
  "Result": {
    "a3": "b3",
    "a2": "b2",
    "a1": "b1"
  }
}

parse_urlquery(query)

['github-issues-event']
| project parsed = parse_urlquery("https://play.axiom.co/axiom-play-qf1k/query?qid=fUKgiQgLjKE-rd7wjy")

Run in Playground

​

replace()

Replace all regex matches with another string.

​

Arguments

• regex: The regular expression to search source. It can contain capture groups in ’(‘parentheses’)’.
• rewrite: The replacement regex for any match made by matchingRegex. Use $0 to refer to the whole match,$1 for the first capture group, $2 and so on for subsequent capture groups.
• source: A string.

​

Returns

• source after replacing all matches of regex with evaluations of rewrite. Matches do not overlap.

​

Examples

replace(regex, rewrite, source)

['sample-http-logs']
| project content_type, Comment = replace("[html]", "[censored]", method)

Run in Playground

​

replace_regex()

Replaces all regex matches with another string.

​

Arguments

• regex: The regular expression to search text.
• rewrite: The replacement regex for any match made by matchingRegex.
• text: A string.

​

Returns

source after replacing all matches of regex with evaluations of rewrite. Matches do not overlap.

​

Examples

replace_regex(@'^logging', 'axiom', 'logging-data')

• Result

{
  "replaced": "axiom-data"
}

replace_regex(regex, rewrite, text)

['github-issues-event']
| extend replaced = replace_regex(@'^logging', 'axiom', 'logging-data')

Run in Playground

​

Backreferences

Backreferences match the same text as previously matched by a capturing group. With Backreferences, you can identify a repeated character or substring within a string.

• Backreferences in APL is implemented using the $ sign.

​

Examples

['github-issues-event']
| project backreferences = replace_regex(@'observability=(.+)', 'axiom=$1', creator)

Run in Playground

​

replace_string()

Replaces all string matches with another string.

​

Arguments

​

Returns

text after replacing all matches of lookup with evaluations of rewrite. Matches don’t overlap.

​

Examples

replace_string("github", "axiom", "The project is hosted on github")

• Result

{
  "replaced_string": "axiom"
}

replace_string(lookup, rewrite, text)

['sample-http-logs']
| extend replaced_string = replace_string("The project is hosted on github", "github", "axiom")
| project replaced_string

Run in Playground

​

reverse()

Function reverses the order of the input Field.

​

Arguments

​

Returns

The reverse order of a field value.

​

Examples

reverse(value)

project reversed = reverse("axiom")

Run in Playground

• Result

moixa

​

split()

Splits a given string according to a given delimiter and returns a string array with the contained substrings.

Optionally, a specific substring can be returned if exists.

​

Arguments

• source: The source string that will be split according to the given delimiter.
• delimiter: The delimiter (Field) that will be used in order to split the source string.

​

Returns

• A string array that contains the substrings of the given source string that are delimited by the given delimiter.

​

Examples

split(source, delimiter)

project split_str = split("axiom_observability_monitoring", "_")

Run in Playground

• Result

{
  "split_str": ["axiom", "observability", "monitoring"]
}

​

strcat()

Concatenates between 1 and 64 arguments.

If the arguments aren’t of string type, they’ll be forcibly converted to string.

​

Arguments

​

Returns

Arguments, concatenated to a single string.

​

Examples

strcat(argument1, argument2[, argumentN])

['github-issues-event']
| project stract_con = strcat( ['milestone.creator'], number )

Run in Playground

['github-issues-event']
| project stract_con = strcat( 'axiom', number )

Run in Playground

• Result

{
  "stract_con": "axiom3249"
}

​

strcat_delim()

Concatenates between 2 and 64 arguments, with delimiter, provided as first argument.

• If arguments aren’t of string type, they’ll be forcibly converted to string.

​

Arguments

​

Returns

Arguments, concatenated to a single string with delimiter.

​

Examples

strcat_delim(delimiter, argument1, argument2[ , argumentN])

['github-issues-event']
| project strcat = strcat_delim(":", actor, creator)

Run in Playground

project strcat = strcat_delim(":", "axiom", "monitoring")

• Result

{
  "strcat": "axiom:monitoring"
}

​

strcmp()

Compares two strings.

The function starts comparing the first character of each string. If they are equal to each other, it continues with the following pairs until the characters differ or until the end of shorter string is reached.

​

Arguments

​

Returns

Returns an integral value indicating the relationship between the strings:

• When the result is 0: The contents of both strings are equal.
• When the result is -1: the first character that does not match has a lower value in string1 than in string2.
• When the result is 1: the first character that does not match has a higher value in string1 than in string2.

​

Examples

strcmp(string1, string2)

['github-issues-event']
| extend cmp = strcmp( body, repo )

Run in Playground

project cmp = strcmp( "axiom", "observability")

• Result

{
  "input_string": -1
}

​

strlen()

Returns the length, in characters, of the input string.

​

Arguments

​

Returns

Returns the length, in characters, of the input string.

​

Examples

strlen(source)

project str_len =  strlen("axiom")

Run in Playground

• Result

{
  "str_len": 5
}

​

strrep()

Repeats given string provided amount of times.

• In case if first or third argument is not of a string type, it will be forcibly converted to string.

​

Arguments

​

Returns

• Value repeated for a specified number of times, concatenated with delimiter.

• In case if multiplier is more than maximal allowed value (1024), input string will be repeated 1024 times.

​

Examples

strrep(value,multiplier,[delimiter])

['github-issues-event']
| extend repeat_string = strrep( repo, 5, "::" )

Run in Playground

project repeat_string = strrep( "axiom", 3, "::" )

• Result

{
  "repeat_string": "axiom::axiom::axiom"
}

​

substring()

Extracts a substring from a source string starting from some index to the end of the string.

​

Arguments

• source: The source string that the substring will be taken from.
• startingIndex: The zero-based starting character position of the requested substring.
• length: A parameter that can be used to specify the requested number of characters in the substring.

​

Returns

A substring from the given string. The substring starts at startingIndex (zero-based) character position and continues to the end of the string or length characters if specified.

​

Examples

substring(source, startingIndex [, length])

['github-issues-event']
| extend extract_string = substring( repo, 4, 5 )

Run in Playground

project extract_string = substring( "axiom", 4, 5 )

{
  "extract_string": "m"
}

​

toupper()

Converts a string to upper case.

toupper("axiom") == "AXIOM"

['github-issues-event']
| project upper = toupper( body )

Run in Playground

​

tolower()

Converts a string to lower case.

tolower("AXIOM") == "axiom"

['github-issues-event']
| project low = tolower( body )

Run in Playground

​

trim()

Removes all leading and trailing matches of the specified cutset.

​

Arguments

• source: A string.
• cutset: A string containing the characters to be removed.

​

Returns

source after trimming matches of the cutset found in the beginning and/or the end of source.

​

Examples

trim(source)

['github-issues-event']
| extend remove_leading_matches = trim( "locked", repo)

Run in Playground

project remove_leading_matches = trim( "axiom", "observability")

• Result

{
  "remove_leading_matches": "bservability"
}

​

trim_regex()

Removes all leading and trailing matches of the specified regular expression.

​

Arguments

• regex: String or regular expression to be trimmed from the beginning and/or the end of source.
• source: A string.

​

Returns

source after trimming matches of regex found in the beginning and/or the end of source.

​

Examples

trim_regex(regex, source)

['github-issues-event']
| extend remove_trailing_match_regex = trim_regex( "^github", action )

Run in Playground

• Result

{
  "remove_trailing_match_regex": "closed"
}

​

trim_end()

Removes trailing match of the specified cutset.

​

Arguments

• source: A string.
• cutset: A string containing the characters to be removed.`

​

Returns

source after trimming matches of the cutset found in the end of source.

​

Examples

trim_end(source)

['github-issues-event']
| extend remove_cutset = trim_end(@"[^\w]+", body)

Run in Playground

• Result

{
  "remove_cutset": "In [`9128d50`](https://7aa98788e07\n), **down**:\n- HTTP code: 0\n- Response time: 0 ms\n"
}

​

trim_end_regex()

Removes trailing match of the specified regular expression.

​

Arguments

• regex: String or regular expression to be trimmed from the end of source.
• source: A string.

​

Returns

source after trimming matches of regex found in the end of source.

​

Examples

trim_end_regex(regex, source)

['github-issues-event']
| project remove_cutset_regex = trim_end_regex( "^github", creator )

Run in Playground

• Result

{
  "remove_cutset_regex": "axiomhq"
}

​

trim_start()

Removes leading match of the specified cutset.

​

Arguments

• source: A string.

​

Returns

• source after trimming match of the specified cutset found in the beginning of source.

​

Examples

trim_start(source)

['github-issues-event']
| project remove_cutset = trim_start( "github", repo)

Run in Playground

• Result

{
  "remove_cutset": "axiomhq/next-axiom"
}

​

trim_start_regex()

Removes leading match of the specified regular expression.

​

Arguments

• regex: String or regular expression to be trimmed from the beginning of source.
• source: A string.

​

Returns

source after trimming match of regex found in the beginning of source.

​

Examples

trim_start_regex(regex, source)

['github-issues-event']
| project remove_cutset = trim_start_regex( "github", repo)

Run in Playground

• Result

{
  "remove_cutset": "axiomhq/next-axiom"
}

​

url_decode()

The function converts encoded URL into a to regular URL representation.

​

Arguments

• encoded url: encoded URL (string).

​

Returns

URL (string) in a regular representation.

​

Examples

url_decode(encoded url)

['github-issues-event']
| project decoded_link = url_decode( "https://www.axiom.co/" )

Run in Playground

• Result

{
  "decoded_link": "https://www.axiom.co/"
}

​

url_encode()

The function converts characters of the input URL into a format that can be transmitted over the Internet.

​

Arguments

• url: input URL (string).

​

Returns

URL (string) converted into a format that can be transmitted over the Internet.

​

Examples

url_encode(url)

['github-issues-event']
| project encoded_url = url_encode( "https://www.axiom.co/" )

Run in Playground

• Result

{
  "encoded_link": "https%3A%2F%2Fwww.axiom.co%2F"
}

​

gettype()

Returns the runtime type of its single argument.

​

Arguments

• Expressions

​

Returns

A string representing the runtime type of its single argument.

​

Examples

​

parse_csv()

Splits a given string representing a single record of comma-separated values and returns a string array with these values.

​

Arguments

• csv_text: A string representing a single record of comma-separated values.

​

Returns

A string array that contains the split values.

​

Examples

parse_csv("axiom,logging,observability") ==  [ "axiom", "logging", "observability" ]

parse_csv("axiom, processing, language")  == [ "axiom", "processing", "language" ]

['github-issues-event']
| project parse_csv("github, body, repo")

Run in Playground