Error using replace regular expression

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1

Hi,

My code is:

system.Text.RegularExpressions.Regex.Replace(mail.Headers(“Message-ID”).tostring,@“[/?%*:”<>.]“,”")

What I am trying to do is remove the set of characters from the message ID header and save that to a string. However, I am getting the compile error “Character is not valid”.

Thanks!

2

@SoqedHozi

Use this syntax mail.Headers(“UID”) at the place of mail.Headers(“Message-ID”)

Cheers

3

I don’t see UID in my mail headers? Does it matter that I’m using outlook?

4

Using UID the error changes to “expression expected”.

5

Is the upper syntax is same as you write in your code.

Because it might show an validation error

Or if it possible can share a workflow where you written this code

6

It’s just an assign activity. The full value is:

system.Text.RegularExpressions.Regex.Replace(mail.Headers(“UID”).tostring,@“[/?%*:”<>.]“,”“)+”.msg"

7

I notice that the \ is not showing in the code above, it follows the /

8

Is this working fine now

9

No I still have that error as mentioned.

10

what basically you want to do?

11

This is so I can use the Message-ID as a unique filename that I can recalculate accurately on demand later in my process. This is because I need to upload the saved mail message.

12

I have tried it also with just 1 character inside the square brackets, and still returns “expression expected”.

13

Hi @SoqedHozi,

Are you trying to remove the characters /?%*:".<>. from message ID?

Regards,
Nimin

14

Correct, along with \ (which isn’t showing in the string when I paste it on here but is present in the assign activity)

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15

I don’t actually know is / and \ appear in message IDs ever to be fair (maybe someone can tell me?), so might not need to replace them at all. However, I get the same error with 1 character in the replacement string.

16

Hi @SoqedHozi,

Please try this.

System.Text.RegularExpressions.Regex.Replace(mail.Headers("Message-ID"),"[<>\/\?%\\\*:\\.""]","")

Warm regards,
Nimin

1 Like
17

Well, the error has disappeared!

I understand the /\ and \, but I don’t understand the \.“” can you break this down for me?

Thanks

1 Like
18

Hi @SoqedHozi,

In order to avoid "." acting as a quantifier in a pattern, "\" is an escape character used to consider "." as a literal. Inside [ ] , '.' normally acts as a literal. but i used "\" just force it to consider as literal .

Inside the activity, "" acts as an escape character to consider " as a literal.

I hope you got it. :slightly_smiling_face:

Warm regards,
Nimin

1 Like
19

Running my program, this assign failed because value cannot be null. It says “parameter name: input”.

Adding the .tostring back in causes a different error on execution - assign: object reference not set to an instance of an object."

20

Hi @SoqedHozi,

mail.Headers(“Message-ID”) is already in string format.

Please make sure you are getting value for “Message-ID”. You can use a writeline activitymail.Headers(“Message-ID”) before doing the regex operation to verify it.

Regards,
Nimin

1 Like