---
title: hash.cityhash64() function
description: >
  `hash.cityhash64()` converts a string value to a 64-bit hexadecimal hash using the CityHash64 algorithm.
menu:
  flux_v0_ref:
    name: hash.cityhash64
    parent: contrib/qxip/hash
    identifier: contrib/qxip/hash/cityhash64
weight: 301

---

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`hash.cityhash64()` converts a string value to a 64-bit hexadecimal hash using the CityHash64 algorithm.



##### Function type signature

```js
(v: A) => string
```

{{% caption %}}
For more information, see [Function type signatures](/flux/v0/function-type-signatures/).
{{% /caption %}}

## Parameters

### v
({{< req >}})
String to hash.




## Examples

### Convert a string to a 64-bit hash using CityHash64

```js
import "contrib/qxip/hash"

hash.cityhash64(v: "Hello, world!")// Returns 2359500134450972198


```