tostring

Use the tostring function to convert various data types to a string representation. This is helpful when you need to normalize values from different sources into string format for string operations, concatenation, or display purposes.

You typically use tostring when working with numeric values, booleans, or other types that need to be converted to strings for string manipulation, formatting, or when combining values in string operations.

Usage

Syntax

tostring(value)

Parameters

Returns

If the expression value is non-null, the result is a string representation of the expression. If the expression value is null, the result is an empty string.

Conversion behavior

The tostring function converts values based on their type:

• Integer: Formatted as base-10 string.
• Float: Formatted using Go’s FormatFloat function with precision -1. For more information, see the Go documentation.
• Boolean: Returns "true" or "false". Nil Boolean values return "false".
• Duration: Returns duration-formatted strings. For example, "1m20s".
• Datetime: Returns RFC3339Nano formatted datetime string.

Use case example

Convert trace attributes to strings for string-based analysis and reporting.

Query

['otel-demo-traces']
| where isnotempty(['attributes.http.response.status_code'])
| extend status_str = tostring(['attributes.http.response.status_code'])
| extend duration_str = tostring(duration)
| extend trace_summary = strcat('Service: ', ['service.name'], ', Status: ', status_str, ', Duration: ', duration_str)
| project _time, trace_id, ['service.name'], status_str, trace_summary

Output

This example converts trace attributes to strings and creates a summary message, enabling formatted trace reporting and analysis.

List of related functions

• strcat: Concatenates strings. Use strcat with tostring to combine converted values into formatted strings.
• strcat-delim: Concatenates strings with a delimiter. Use strcat-delim with tostring to join converted values with separators.
• toint: Converts input to integer. Use toint to convert strings back to integers when needed.

Other query languages