Extract a substring using PowerShell

Question

How can I extract a substring using PowerShell   I have this string       -----start-------Hello World------end-------    I have to extract      Hello World   What is the best way to do that

User · Answer

Not sure if this is efficient or not  but strings in PowerShell can be referred to using array index syntax  in a similar fashion to Python   It s not completely intuitive because of the fact the first letter is referred to by index   0  but it does    Allow a second index number that is longer than the string  without generating an error Extract substrings in reverse Extract substrings from the end of the string   Here are some examples   PS  gt   Hello World  0  2    Yields the result  index values included for clarity - not generated in output    H  0  e  1  l  2    Which can be made more useful by passing -join      PS  gt   Hello World  0  2  -join    Hel   There are some interesting effects you can obtain by using different indices   Forwards  Use a first index value that is less than the second and the substring will be extracted in the forwards direction as you would expect  This time the second index value is far in excess of the string length but there is no error   PS  gt   Hello World  3  300  -join    lo World   Unlike   PS  gt   Hello World  Substring 3 300  Exception calling  Substring  with  2  argument s    Index and length must refer to a location within the string    Backwards  If you supply a second index value that is lower than the first  the string is returned in reverse   PS  gt   Hello World  4  0  -join    olleH   From End  If you use negative numbers you can refer to a position from the end of the string  To extract  World   the last 5 letters  we use   PS  gt   Hello World  -5  -1  -join    World

User · Answer

I needed to extract a few lines in a log file and this post was helpful in solving my issue  so i thought of adding it here  If someone needs to extract muliple lines  you can use the script to get the index of the a word matching that string  i m searching for  Root   and extract content in all lines    File content   Get-Content  Path of the text file   result        foreach   val in  File content        Index No    val IndexOf  Root        result     val substring  Index No      result   Select-Object -Unique   Cheers

User · Answer

other solution   template  -----start------- Value This is a test 123 ------end-------   text  -----start-------Hello World------end-------    text   ConvertFrom-String -TemplateContent  template

User · Answer

The -match operator tests a regex  combine it with the magic variable  matches to get your result  PS C   gt   x    ----start----Hello World----end----  PS C   gt   x -match  ----start----   lt content gt    ----end----  True PS C   gt   matches  content   Hello World   Whenever in doubt about regex-y things  check out this site  http   www regular-expressions info

User · Answer

Since the string is not complex  no need to add RegEx strings  A simple match will do the trick   line    ----start----Hello World----end----   line -match  Hello World   matches 0  Hello World   result    matches 0   result Hello World

User · Answer

PS gt   a    -----start-------Hello World------end-------  PS gt   a substring 17  11           or PS gt   a Substring  a IndexOf  H    11      a Substring argument1  argument2  --  Here argument1   Starting position of the desired alphabet and argument2   Length of the substring you want as output    Here 17 is the index of the alphabet  H  and since we want to Print till Hello World  we provide 11 as the second argument

User · Answer

Building on Matt s answer  here s one that searches across newlines and is easy to modify for your own use   String  ----start---- nHello World n----end----   SearchStart  ----start---- n   Will not be included in results  SearchEnd   n----end----   Will not be included in results  String -match    s  SearchStart   lt content gt     SearchEnd   result  matches  content    result   --  NOTE  if you want to run this against a file keep in mind Get-Content returns an array not a single string   You can work around this by doing the following    String  string   join   n    Get-Content  Filename

User · Answer

The Substring method provides us a way to extract a particular string from the original string based on a starting position and length  If only one argument is provided  it is taken to be the starting position  and the remainder of the string is outputted   PS  gt   test string  Substring 0 4  Test PS  gt   test string  Substring 4   stringPS  gt    link text  But this is easier       s    Hello World is in here Hello World     p    Hello World    s -match  p   And finally  to recurse through a directory selecting only the  txt files and searching for occurrence of  Hello World    dir -rec -filter   txt   Select-String  Hello World

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