If you didn't want to use a Third-Party solution, you can use Office Scripts within Excel. The first thing you will need to do is create a script that you can then use within Power Automate.
It's important to note that when you create an Office Script it's stored in your One Drive, and if you want others to use it you will need to share it with them. There is now an option to save your Office Scripts in a SharePoint Library, but unfortunately (at this stage) you can't then use them within Power Automate.
To create a new Office Script, create/open an Excel File in the Browser and click on Automate on the Toolbar, then click on New Script.
In the Script code editor that appears, Rename the script to something like regExMatch, then paste in the following which is a script that uses Regex.
function main(
workbook: ExcelScript.Workbook,
searchString: string,
regexPattern: string,
regexFlags: string): Array<string> {
const matches: Array<string> = [];
const re = new RegExp(regexPattern, regexFlags);
const matchArray: Array<string> = searchString.match(re);
if (matchArray) {
matchArray.forEach(m => matches.push(m))
}
return matches;
}
You can now use that script in any of your Power Automates.
For your requirement, see the flow below. I'll go into each of the actions.
Compose holds the data you want to check which may or may not contain characters.
Run script is an Excel Online action that you can use. It doesn't matter what Excel file you choose here as the Office Script itself lives in your OneDrive.
Script will be the script that you just created. It should show up as an option to select.
searchString is the text you want to check. In this case it's whatever is stored in our Compose.
regexPattern is the same as @v-chengfen-msft provided which will match if the searchString contains only numbers.
regexFlags has g to not just look at the first match.
The result will be either an array of matches, or if no matches, an empty array. So, your Condition can check the length of the result (array). If it equals 0 then the text must have included characters other than numbers. If it contains 1 or more items in the array, then it only includes numbers.
The expression to check the length of the array is:
length(outputs('Run_script')?['body/result'])
