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Oct 16, 2025
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Document ToString() conversion for F# interpolated strings #49134

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Document ToString() conversion for F# interpolated strings
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Update docs/fsharp/language-reference/interpolated-strings.md
BillWagner Oct 15, 2025
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4 changes: 4 additions & 0 deletions docs/fsharp/language-reference/interpolated-strings.md
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title: Interpolated strings
description: Learn about interpolated strings, a special form of string that allows you to embed F# expressions directly inside them.
ms.date: 10/01/2025
ai-usage: ai-assisted
---

# Interpolated strings
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The contents in between each `{}` brace pair can be any F# expression.

For non-typed interpolated strings (without format specifiers), the expression is converted to a string using the `ToString()` method. If the expression evaluates to `null`, an empty string is used.

For typed interpolated strings with format specifiers (such as `%s{expr}` or `%d{expr}`), the conversion follows the rules defined for that specific format specifier.
To escape a `{}` brace pair, write two of them like so:

```fsharp
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