Regular Expressions

12-Jun-22 5:17

Friends,
I am using PowerShell.
I am trying to write a regex match pattern for a string that has ALL these qualifications:
1. Must have one and only one period in the string.
A. At least one Alpha, A-Za-z before the period.
B. At least one Alpha, A-Z Za-z after the period.
2. The last character in the string must be numeric, 0-9 No Alpha, A-Za-z
3. The second-to-the-last character must be one of these two:
A. May be Alpha, , A-Z Za-z or
B. May be numeric, 0-9
4. No Numerics, 0-9 Allowed except the last two characters in the string.

Examples of good ones:
Joe.Jones1
Joe.Jones01
J.J1
j.j99
jo.jn01
jo.j1

I have written many small pieces of code that could be pieced together using -AND for many matches but surely there is a way to make some one-liner that can incorporate all of these.
I may be able to do it using -AND like this:
$test -notmatch “[0-9]” -AND $test -NOTmatch “[\.]" -AND $test -match “[a-zA-Z]" -AND $test -NOTmatch “[@#$%^&*()]"

But I would like to be eloquent and do something like this:
$GoodPatternCheck = $PossibleGoodName -match '.+,.+,.+,.+'
If ( $GoodPatternCheck )

I have written many short matches in my learning process which I plan on sharing with my co-workers who are also novices.
I don't see any way to attach a file here, so here is an example of the kinds of short piece of code I write and test to help me learn:
$test = "Now......... is t.he, tim,e"
Write-Host ‘$test’ $test
$Count = ($test.Split('\.')).count -1
Write-Host ‘$test’ $test
Write-Host ‘$Count’ $Count

Thank you in advance for your help on this.

-- modified 12-Jun-22 10:58am.

Peter_in_278012-Jun-22 6:05

Peter_in_2780

12-Jun-22 6:05

You may need to tweak bits of this to suit PowerShell's regex engine, but the idea should work.

[A-Za-z]+\.[A-Za-z]+[A-Za-z0-9]?[0-9]

In words: one or more alpha, a literal period, one or more alpha, an optional alphanumeric, one numeric.

Software rusts. Simon Stephenson, ca 1994. So does this signature. me, 2012

Member 1567083112-Jun-22 7:22

12-Jun-22 7:22

Peter, you must be some kind of genius! I thought it would take days for somebody to figure this out. Here is what works on my PowerShell ISE:

'[A-Za-z]'+'[\.]' + '[A-Za-z]+[A-Za-z0-9]?[0-9]'

Perfect! Thanks!
Now I will go study what the question mark means ?

OriginalGriff12-Jun-22 7:23

OriginalGriff

12-Jun-22 7:23

"As few as possible"
Is you are going to play with Regular Expressions, then you need a tool. Get a copy of Expresso[^] - it's free, and it examines and generates Regular expressions.

"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
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Member 1567083112-Jun-22 8:38

12-Jun-22 8:38

OriginalGriff, Thanks for the information, I will look at that! Yes, I think I need a tool.
I just found Regex101.com also. I don't know how these work yet, I hope I can get these to work.

Member 1567083112-Jun-22 9:13

12-Jun-22 9:13

Peter, I was too hasty, Here is what works best:
'[A-Za-z]'+'[\.]' + '[A-Za-z]'+'[A-Za-z0-9]?[0-9]'

Member 1567083112-Jun-22 8:32

12-Jun-22 8:32

Peter, I was too hasty again.
The problem is:
This is supposed to match: Joe.Jone2
Not supposed to match: Joe.Jone222

I am using: [A-Za-z]'+'[\.]' + '[A-Za-z]+[A-Za-z0-9]?[0-9] Matches Joe.Jone2 Also Matches Joe.Jones22
Prolem is, it also matches Joe.Jones222
Only the last two may be numeric.

Examples of good ones:
Joe.Jones1
Joe.Jones01
J.J1
j.j99
jo.jn01
jo.j1

Examples of ones that I do not want to match, Bad ones:
Joe.Jones222
Joe2.Jones1
Joe.2Jones01

I am testing/playing with: [A-Za-z]'+'[\.]' + '[A-Za-z]'+'[A-Za-z0-9]?[0-9]

Member 1567083112-Jun-22 12:49

12-Jun-22 12:49

Peter, I am having better luck by adding two Dollar Signs $ at the end.
The last Test below here is the only problem now.

I want J.j1 to be true too.

Here are the tests:
PS C:\Users\gmsab> "j.jo1" -match '[A-Za-z]'+'[\.]' + '[A-Za-z]+[A-Za-z0-9]$?[0-9$]$'
True

PS C:\Users\gmsab> "joe.jones11" -match '[A-Za-z]'+'[\.]' + '[A-Za-z]+[A-Za-z0-9]$?[0-9$]$'
True

PS C:\Users\gmsab> "j.jones11" -match '[A-Za-z]'+'[\.]' + '[A-Za-z]+[A-Za-z0-9]$?[0-9$]$'
True

PS C:\Users\gmsab> "j.jones1" -match '[A-Za-z]'+'[\.]' + '[A-Za-z]+[A-Za-z0-9]$?[0-9$]$'
True

PS C:\Users\gmsab> "j.jones" -match '[A-Za-z]'+'[\.]' + '[A-Za-z]+[A-Za-z0-9]$?[0-9$]$'
False

PS C:\Users\gmsab> "j.jones221" -match '[A-Za-z]'+'[\.]' + '[A-Za-z]+[A-Za-z0-9]$?[0-9$]$'
False

PS C:\Users\gmsab> "j.j21" -match '[A-Za-z]'+'[\.]' + '[A-Za-z]+[A-Za-z0-9]$?[0-9$]$'
True

PS C:\Users\gmsab> "j.j1" -match '[A-Za-z]'+'[\.]' + '[A-Za-z]+[A-Za-z0-9]$?[0-9$]$'
False

Peter_in_278012-Jun-22 13:36

Peter_in_2780

12-Jun-22 13:36

Too many $. In all the regex engines I use (I don't do PowerShell), $ matches the end of the input string. I forgot that off my original answer, sorry. It should be there to disallow trailing garbage.
Similarly you probably need a ^ at the start to match start of string.

In regex,
* means "0 or any number of occurrences of the previous item"
+ means "1 or more occurrences..."
? means "0 or 1 occurrences..."
. matches any character, so to match a literal period, you need to escape it with \
So your regex should finally be
^[A-Za-z]+\.[A-Za-z]+[A-Za-z0-9]?[0-9]$
only adding whatever delimiters and escapes are required by PowerShell (which should probably be just ' ' around the whole exprerssion).

Software rusts. Simon Stephenson, ca 1994. So does this signature. me, 2012

Member 1567083112-Jun-22 14:46

12-Jun-22 14:46

Peter, I have tested this as you said:
^[A-Za-z]+\.[A-Za-z]+[A-Za-z0-9]?[0-9]$

I cannot make it fail with any of my inputs, good input and bad input, it returns True and False at all the right places.
I will stress test it again tomorrow.

And I will study all this too.
Many Thanks......

Peter_in_278012-Jun-22 16:42

Peter_in_2780

12-Jun-22 16:42

You're welcome.
And keep studying. Don't just stop because your immediate problem is solved.

Software rusts. Simon Stephenson, ca 1994. So does this signature. me, 2012

Adresse erfassen mittels RegEx

Member 1311558125-Sep-23 17:07

Member 13115581

25-Sep-23 17:07

why not this?

^[A-z]+\.[A-z]+\d{1,2}$

Member 156568991-Jun-22 4:26

Member 15656899

1-Jun-22 4:26

Hello all,

I have a question regarding regex address capture.

I have the following address:

Harald Sturm
Schönstrasse 18a
60311 Frankfurt am Main

I want to split this string into 4 components with 4 different regex to do that.

Name: Harald Sturm. (The whole first line)
Street: Schönstrasse 18a (The whole second line)
ZIP CODE: 60311 (First digital part of the sentence )
Location: Frankfurt am Main (Last part of the sentence)

Question for the regex experts: What would each regex expression for this look like ?

Many thanks in advance.

OriginalGriff1-Jun-22 2:53

OriginalGriff

1-Jun-22 2:53

To be honest, unless your addresses are pretty rigidly controlled, you are probably on a loser even trying: Extract addressline, state, city, zipcode into different columns from one single column called “adress” with space as delimeter using posgresql[^]

But ...

(?<Name>.+?)\r\n(?<Street>.+?)\r\n(?<Zip>\d+?)\s+(?<Town>.+)

May do it ... I needed to play with regex options Mutiline = true, SingleLine = true and change "$" to "\r\n" to get it working in Expresso.

Member 156568991-Jun-22 12:39

Member 15656899

1-Jun-22 12:39

I don't have a label like name, street etc- I just always have three lines.

The first line always records the full name.
The second line records the street including the house number.
The third line consists of a postal code and city. Thereby
the postal code and the city should be extracted separately.

I would need four single regex rules at last.

Thanks a lot in advance

OriginalGriff1-Jun-22 19:59

OriginalGriff

1-Jun-22 19:59

Did you try the regex I supplied? At all?

Richard MacCutchan1-Jun-22 23:01

Richard MacCutchan

1-Jun-22 23:01

A few lines of code including one call to String.Split would do that much quicker than a regex.