How do I Search Find and Replace in a standard string

Question

Is there a way to replace all occurrences of a substring with another string in std  string   For instance   void SomeFunction std  string amp  str       str   str replace  hello    world       lt  I m looking for something nice like this

User · Answer

In C  11  you can do this as a one-liner with a call to regex replace    include  lt string gt   include  lt regex gt   using std  string   string do replace  string const  amp  in  string const  amp  from  string const  amp  to       return std  regex replace  in  std  regex from   to       string test    Remove all spaces   std  cout  lt  lt  do replace test            lt  lt  std  endl    output   Removeallspaces

User · Answer

I believe this would work  It takes const char  s as a parameter     params find and replace cannot be NULL void FindAndReplace  std  string amp  source  const char  find  const char  replace          ASSERT find    NULL        ASSERT replace    NULL      size t findLen   strlen find      size t replaceLen   strlen replace      size t pos   0        search for the next occurrence of find within source    while   pos   source find find  pos      std  string  npos               replace the found string with the replacement       source replace  pos  findLen  replace             the next line keeps you from searching your replace string           so your could replace  hello  with  hello world           and not have it blow chunks        pos    replaceLen

User · Answer

My templatized inline in-place find-and-replace   template lt class T gt  int inline findAndReplace T amp  source  const T amp  find  const T amp  replace        int num 0      typename T  size t fLen   find size        typename T  size t rLen   replace size        for  T  size t pos 0   pos source find find  pos    T  npos  pos  rLen                num            source replace pos  fLen  replace             return num      It returns a count of the number of items substituted  for use if you want to successively run this  etc   To use it   std  string str    one two three   int n   findAndReplace str   one    1

User · Answer

Replace all occurrences of searchStr in str with replacer    Each match is replaced only once to prevent an infinite loop    The algorithm iterates once over the input and only concatenates     to the output  so it should be reasonably efficient std  string replace const std  string amp  str  const std  string amp  searchStr       const std  string amp  replacer           Prevent an infinite loop if the input is empty     if  searchStr                  return str             std  string result           size t pos   0      size t pos2   str find searchStr  pos        while  pos2    std  string  npos            result    str substr pos  pos2-pos    replacer          pos   pos2   searchStr length            pos2   str find searchStr  pos              result    str substr pos  str length  -pos       return result

User · Answer

The easiest way  offering something near what you wrote  is to use Boost Regex  specifically regex replace   std  string has built in find   and replace   methods  but they are more cumbersome to work with as they require dealing with indices and string lengths

User · Answer

Why not return a modified string   std  string ReplaceString std  string subject  const std  string amp  search                            const std  string amp  replace        size t pos   0      while  pos   subject find search  pos      std  string  npos             subject replace pos  search length    replace            pos    replace length              return subject      If you need performance  here is an optimized function that modifies the input string  it does not create a copy of the string   void ReplaceStringInPlace std  string amp  subject  const std  string amp  search                            const std  string amp  replace        size t pos   0      while  pos   subject find search  pos      std  string  npos             subject replace pos  search length    replace            pos    replace length              Tests   std  string input    abc abc def   std  cout  lt  lt   Input string     lt  lt  input  lt  lt  std  endl   std  cout  lt  lt   ReplaceString   return value                lt  lt  ReplaceString input   bc          lt  lt  std  endl  std  cout  lt  lt   ReplaceString   input string not changed                lt  lt  input  lt  lt  std  endl   ReplaceStringInPlace input   bc          std  cout  lt  lt   ReplaceStringInPlace   input string modified                lt  lt  input  lt  lt  std  endl    Output   Input string  abc abc def ReplaceString   return value  a   a   def ReplaceString   input string not modified  abc abc def ReplaceStringInPlace   input string modified  a   a   def

User · Answer

include  lt string gt   using std  string   void myReplace string amp  str                 const string amp  oldStr                 const string amp  newStr      if  oldStr empty          return         for  size t pos   0   pos   str find oldStr  pos      string  npos         str replace pos  oldStr length    newStr       pos    newStr length            The check for oldStr being empty is important  If for whatever reason that parameter is empty you will get stuck in an infinite loop   But yeah use the tried and tested C  11 or Boost solution if you can

User · Answer

Why not implement your own replace   void myReplace std  string amp  str                 const std  string amp  oldStr                 const std  string amp  newStr      std  string  size type pos   0u    while  pos   str find oldStr  pos      std  string  npos        str replace pos  oldStr length    newStr        pos    newStr length

User · Answer

include  lt boost algorithm string hpp gt     include Boost  a C   library     std  string target  Would you like a foo of chocolate  Two foos of chocolate     boost  replace all target   foo    bar      Here is the official documentation on replace all

[c++] How do I Search/Find and Replace in a standard string?

Examples related to c++

Examples related to replace

Examples related to std