Conditions in Power Automate

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Prerequisites for this session

• good general digital skills
• prior experience of writing your own Flows in Power Automate
• appropriate M365 access and permissions for Power Automate, Teams, and OneDrive

Introduction

• Control flow is the technical term that coders use to describe software that changes its behaviour depending on circumstances.
• This session looks at using variables and conditions to do control flow in Power Automate

Plan

• We’ll build a series of H&SC-relevant mini-projects:
  • connecting to a OneDrive folder
  • counting files in that folder
  • posting a count of those files in a Teams message
  • varying the text of that Teams message by count
  • varying the content of that Teams message by the time of day (or day of week…)

Project one: connect with a OneDrive folder

• we’ll start with a very basic Flow that connects to a directory of files in your OneDrive.

Setup

• download the sample files, and extract to your OneDrive
• or, create a directory in your OneDrive containing some text files, labelled 0.txt, 1.txt, 2.txt…9.txt
• create a new instant flow
• after the Manually trigger a flow box, add a List files in folder connector
  
• supply the address of your directory of text files in the List files in folder connector
• save and test your flow

Tip

• don’t expect any interesting output, but do run this flow to check for errors and permissions
• in the next project, we’ll collect part of the information that Power Automate makes available about your files
• Power Automate has connectors for most network/cloud file storage platform, so this approach should be adaptable to whatever platform you use

Project two: counting files

• we’ll now update that flow to count the number of files in the folder
• we’ll need to create variables to hold that number
• in later stages, we’ll then pass that count variable into some useful output (like a Teams message)

Task

• add an Initialize variable block
  
• now populate the Initialize variable fields as shown below:
  
  • give your variable a name: file_content
  • set the type, which tells Power Automate what sort of value to expect: array
  • finally, set a starting value: body/value

• we now have our file_content variable that contains all our file info
• in a real flow, we’d probably want to put other parts of that to use
• but in this simple example, we’ll just count the number of entries (= the number of files in our directory)

Task

• add a second Initialize variable block
• populate the fields as shown below:
  • give your variable a name: file_count
  • set the type, which tells Power Automate what sort of value to expect: integer
  • finally, set a starting value. That’s more involved than the previous variable: you need to write a formula to calculate the length of your file_content - length(variables('file_content'))
    

• that should leave you with a flow like the following, which you should save and test:
  
• once run, you should see that the value of file_count is 10
  

Digression: data types

• a note on data types: Power Automate has several different built-in data types:
  
• Power Automate is inflexible about data types: so, for example, if you accidentally try to set an integer to 2.4, your flow will fail
• you’ll need to think carefully about what sort of value your variable is intended to hold

Project three: posting a count of those files in a Teams message

This one should be easy! At least, once you’ve been added to the KIND test Team…

Task

• add a Post message in a chat or channel connector
• populate the fields - it’s recommended to post as User as this allows you to edit any embarrasing errors in your posts once they’ve been posted
• for the message, write some suitable text, then include the file_count variable
  

Sample Teams output

Project 4: varying the text of that Teams message by count

• so far, our message just repeats the contents of file_count with a bit of static text
• we can use a Condition to change the text that accompanies that value
  
• we should be able to adapt our previous flow to use that condition

Project 5: varying text by time of day

• we could now add another variable to our flow
• this will set a value based on the time of day
  
• we can set our condition to use this variable instead of file_count