Delete specific line from a text file

Question

I need to delete an exact line from a text file but I cannot for the life of me workout how to go about doing this   Any suggestions or examples would be greatly appreciated   Related Questions  Efficient way to delete a line from a text file  C

User · Answer

Are you on a Unix operating system   You can do this with the  sed  stream editor  Read the man page for  sed

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You can actually use C  generics for this to make it real easy           var file   new List lt string gt  System IO File ReadAllLines  C   path             file RemoveAt 12           File WriteAllLines  C   path   file ToArray

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I cared about the file s original end line characters   quot  n quot  or  quot  r n quot   and wanted to maintain them in the output file  not overwrite them with what ever the current environment s char s  are like the other answers appear to do   So I wrote my own method to read a line without removing the end line chars then used it in my DeleteLines method  I wanted the option to delete multiple lines  hence the use of a collection of line numbers to delete   DeleteLines was implemented as a FileInfo extension and ReadLineKeepNewLineChars a StreamReader extension  but obviously you don t have to keep it that way   public static class FileInfoExtensions       public static FileInfo DeleteLines this FileInfo source  ICollection lt int gt  lineNumbers  string targetFilePath                var lineCount   1           using  var streamReader   new StreamReader source FullName                         using  var streamWriter   new StreamWriter targetFilePath                                 string line                   while   line   streamReader ReadLineKeepNewLineChars       null                                        if   lineNumbers Contains lineCount                                                 streamWriter Write line                                              lineCount                                                       return new FileInfo targetFilePath            public static class StreamReaderExtensions       private const char EndOfFile     uffff             lt summary gt          Reads a line  similar to ReadLine method  but keeps any         new line characters  e g   quot  r n quot  or  quot  n quot             lt  summary gt      public static string ReadLineKeepNewLineChars this StreamReader source                if  source    null              throw new ArgumentNullException nameof source             char ch    char source Read             if  ch    EndOfFile              return null           var sb   new StringBuilder             while  ch     EndOfFile                        sb Append ch                if  ch      n                   break               ch    char  source Read                       return sb ToString

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What   Use file open  seek position then  stream erase line using null   Gotch it  Simple stream no array that eat memory fast   This work on vb   Example search line culture id where culture are namevalue and id are value and we want to change it to culture en  Fileopen 1   text ini   dim line as string dim currentpos as long while true     line   lineinput 1      dim namevalue   as string   split line           if namevalue 0     line name value that i want to edit  then         currentpos   seek 1          fileclose           dim fs as filestream  test ini   filemode open          dim sw as streamwriter fs          fs seek currentpos  seekorigin begin          sw write null          sw write namevalue         newvalue          sw close           fs close           exit while     end if     msgbox  org ternate jua bisa  no line found   end while   that s all  use  d

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Read and remember each line  Identify the one you want to get rid of Forget that one Write the rest back over the top of the file

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This can be done in three steps      1  Read the content of the file string   readText   File ReadAllLines path       2  Empty the file File WriteAllText path  String Empty       3  Fill up again  but without the deleted line using  StreamWriter writer   new StreamWriter path         foreach  string s in readText                if   s Equals lineToBeRemoved                         writer WriteLine s

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The best way to do this is to open the file in text mode  read each line with ReadLine    and then write it to a new file with WriteLine    skipping the one line you want to delete   There is no generic delete-a-line-from-file function  as far as I know

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No rocket scien code require  Hope this simple and short code will help   List linesList   File ReadAllLines  myFile txt   ToList                linesList RemoveAt 0   File WriteAllLines  myFile txt    linesList ToArray       OR use this  public void DeleteLinesFromFile string strLineToDelete                string strFilePath    Provide the path of the text file           string strSearchText   strLineToDelete          string strOldText          string n               StreamReader sr   File OpenText strFilePath           while   strOldText   sr ReadLine       null                        if   strOldText Contains strSearchText                                 n    strOldText   Environment NewLine                                  sr Close            File WriteAllText strFilePath  n

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One way to do it if the file is not very big is to load all the lines into an array   string   lines   File ReadAllLines  filename txt    string   newLines   RemoveUnnecessaryLine lines   File WriteAllLines  filename txt   newLines

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If the line you want to delete is based on the content of the line   string line   null  string line to delete    the line i want to delete    using  StreamReader reader   new StreamReader  C   input          using  StreamWriter writer   new StreamWriter  C   output              while   line   reader ReadLine       null                if  String Compare line  line to delete     0                  continue               writer WriteLine line                       Or if it is based on line number   string line   null  int line number   0  int line to delete   12   using  StreamReader reader   new StreamReader  C   input          using  StreamWriter writer   new StreamWriter  C   output              while   line   reader ReadLine       null                line number                 if  line number    line to delete                  continue               writer WriteLine line

[c#] Delete specific line from a text file?

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