Changing a numerical value in a text file using PowerShell - powershell

Question

Im looking for a solution that will allow me to modify numerical values(xyz values) in a line of text using the Get-Content cmdlet and write those vales back to the text file. I have a text file "MyFile.txt" with lines of text as follows"
COMPONENT-IDENTIFIER 1
ATTRIBUTE9 C
ATTRIBUTE22 0
END-POINT 518700.500 555700.500 33234.800 1 SL
END-POINT 518500.500 555700.500 33234.800 1 SL
WEIGHT 2.177
UBV {111256-254885-000-1515-BGL518FS7D}
END-POINT 518700.500 555700.500 33234.800 1 PL
END-POINT 518500.500 555700.500 33234.800 1 PL
ATTRIBUTE15 D
ATTRIBUTE08 3
Basically i need to find the -Pattern "END-POINT" and parse the line and change the numerical values for the first three double values and write it back to the text file (text file delimiters are odd - four spaces). I just need to perform basic math like add, subtract and or divide. The file is large and has multiple attributes and other values that i do not need to modify only the "END-POINT" values.
here is what i have, cant quiet figure out how to replace the values, im not sure if its even the right direction:
$MyFile = Get-Content "MyFile.txt"
ForEach ($line in $MyFile){
if ($line | select-String -Pattern 'END-POINT'){
$Array = #($line)
$NewArray = $Array -split " "
$Arrayx = $NewArray.split(" ")[2]/12.0
$Arrayy = $NewArray.split(" ")[2]/12.0
$Arrayx = $NewArray.split(" ")[2]/12.0
}
}
Appreciate any insight in advance.

Answer 1

In order to update these numeric END-POINT values, I'd suggest you use switch with option -Regex and loop through the file line-by-line:
$endPointRegex = '(?<endpoint>\s*END-POINT\s{4})(?<num1>\d+(?:\.\d+))?\s+(?<num2>\d+(?:\.\d+))?\s+(?<num3>\d+(?:\.\d+))?(?<rest>.*)'
$result = switch -Regex -File 'D:\Test\MyFile.txt' {
$endPointRegex {
'{0}{1} {2} {3}{4}' -f $matches['endpoint'],
([double]$matches['num1'] / 12.0),
([double]$matches['num2'] / 12.0),
([double]$matches['num3'] / 12.0),
$matches['rest']
}
default { $_ }
}
# output on screen
$result
# output to new file
$result | Set-Content -Path 'D:\Test\MyNewFile.txt' -Force
Output:
COMPONENT-IDENTIFIER 1
ATTRIBUTE9 C
ATTRIBUTE22 0
END-POINT 43225.0416666667 46308.375 2769.56666666667 1 SL
END-POINT 43208.375 46308.375 2769.56666666667 1 SL
WEIGHT 2.177
UBV {111256-254885-000-1515-BGL518FS7D}
END-POINT 43225.0416666667 46308.375 2769.56666666667 1 PL
END-POINT 43208.375 46308.375 2769.56666666667 1 PL
ATTRIBUTE15 D
ATTRIBUTE08 3
If you want the numbers devided by 12.0 also have 3 decimals like the original values, change to:
$endPointRegex = '(?<endpoint>\s*END-POINT\s{4})(?<num1>\d+(?:\.\d+))?\s+(?<num2>\d+(?:\.\d+))?\s+(?<num3>\d+(?:\.\d+))?(?<rest>.*)'
$result = switch -Regex -File 'D:\Test\MyFile.txt' {
$endPointRegex {
'{0}{1:F3} {2:F3} {3:F3}{4}' -f $matches['endpoint'],
([double]$matches['num1'] / 12.0),
([double]$matches['num2'] / 12.0),
([double]$matches['num3'] / 12.0),
$matches['rest']
}
default { $_ }
}
# output on screen
$result
# output to new file
$result | Set-Content -Path 'D:\Test\MyNewFile.txt' -Force
Output:
COMPONENT-IDENTIFIER 1
ATTRIBUTE9 C
ATTRIBUTE22 0
END-POINT 43225.042 46308.375 2769.567 1 SL
END-POINT 43208.375 46308.375 2769.567 1 SL
WEIGHT 2.177
UBV {111256-254885-000-1515-BGL518FS7D}
END-POINT 43225.042 46308.375 2769.567 1 PL
END-POINT 43208.375 46308.375 2769.567 1 PL
ATTRIBUTE15 D
ATTRIBUTE08 3
Regex details:
(?<endpoint> Match the regular expression below and capture its match into backreference with name “endpoint”
\s Match a single character that is a “whitespace character” (spaces, tabs, line breaks, etc.)
* Between zero and unlimited times, as many times as possible, giving back as needed (greedy)
END-POINT Match the characters “END-POINT” literally
\s Match a single character that is a “whitespace character” (spaces, tabs, line breaks, etc.)
{4} Exactly 4 times
)
(?<num1> Match the regular expression below and capture its match into backreference with name “num1”
\d Match a single digit 0..9
+ Between one and unlimited times, as many times as possible, giving back as needed (greedy)
(?: Match the regular expression below
\. Match the character “.” literally
\d Match a single digit 0..9
+ Between one and unlimited times, as many times as possible, giving back as needed (greedy)
)
)? Between zero and one times, as many times as possible, giving back as needed (greedy)
\s Match a single character that is a “whitespace character” (spaces, tabs, line breaks, etc.)
+ Between one and unlimited times, as many times as possible, giving back as needed (greedy)
(?<num2> Match the regular expression below and capture its match into backreference with name “num2”
\d Match a single digit 0..9
+ Between one and unlimited times, as many times as possible, giving back as needed (greedy)
(?: Match the regular expression below
\. Match the character “.” literally
\d Match a single digit 0..9
+ Between one and unlimited times, as many times as possible, giving back as needed (greedy)
)
)? Between zero and one times, as many times as possible, giving back as needed (greedy)
\s Match a single character that is a “whitespace character” (spaces, tabs, line breaks, etc.)
+ Between one and unlimited times, as many times as possible, giving back as needed (greedy)
(?<num3> Match the regular expression below and capture its match into backreference with name “num3”
\d Match a single digit 0..9
+ Between one and unlimited times, as many times as possible, giving back as needed (greedy)
(?: Match the regular expression below
\. Match the character “.” literally
\d Match a single digit 0..9
+ Between one and unlimited times, as many times as possible, giving back as needed (greedy)
)
)? Between zero and one times, as many times as possible, giving back as needed (greedy)
(?<rest> Match the regular expression below and capture its match into backreference with name “rest”
. Match any single character that is not a line break character
* Between zero and unlimited times, as many times as possible, giving back as needed (greedy)
)
Mind you, these numbers will format with decimal comma's if you are in a country that uses the decimal comma instead of a decimal point. Since you're in Houston, you won't have to deal with that

Answer 2

convert to xml file, search for END-POINT using regular expression, edit, and convert back
https://en.wikipedia.org/wiki/Regular_expression
https://en.wikipedia.org/wiki/XML