> For the complete documentation index, see [llms.txt](https://docs.inforiver.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.inforiver.com/formula-syntax/text-formatting-functions/replace.md).
# REPLACE
Replaces part of a text string with different text based on the position and number of characters you specify.
The REPLACE function replaces an input text string with a given value for a specified index and length. Node references are also accepted as arguments. The index starts at 1 i.e. the first character of the input string will have an index of 1.
### Syntax
```javascript
replace(old_string:string, index:number, length:number, replace_text:string)
```
### Arguments
old\_string- A text string.Required.
index- A number indicating the position at which the string should be replaced.Required.
length- A number indicating the number of characters to be replaced in the input string.Required.
replace\_text- A text string that will replace a part/all of the old\_string parameter.Required.
### Example
```javascript
REPLACE('INFORIVER', 1, 4, 'LUMEL')
//Returns “LUMELRIVER"
```
Replace function
### **Excel equivalent**
[**Replace**](https://support.microsoft.com/en-us/office/replace-function-8d799074-2425-4a8a-84bc-82472868878a)
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