Ruby remove last N characters from a string

Question

What is the preferred way of removing the last n characters from a string

User · Answer

You can always use something like     string  sub     X          Where X is the number of characters to remove   Or with assigning using the result   myvar    string  0  -X    where X is the number of characters plus one to remove

User · Answer

If you re ok with creating class methods and want the characters you chop off  try this   class String   def chop multiple amount      amount times inject  self          s  r    s chop  r prepend s -1        end end  hello  world    hello world  chop multiple 5 hello    gt   hello   world    gt   world

User · Answer

name    my text  x times do name chop  end   Here in the console    gt name    Nabucodonosor     gt   Nabucodonosor    gt  7 times do name chop  end    gt  7   gt  name    gt   Nabuco

User · Answer

str   str 0   -n

User · Answer

x    my test  last char   x split     last

User · Answer

Ruby 2 5   As of Ruby 2 5 you can use delete suffix or delete suffix  to achieve this in a fast and readable manner   The docs on the methods are here   If you know what the suffix is  this is idiomatic  and I d argue  even more readable than other answers here     abc123  delete suffix  123           gt   abc   abc123  delete suffix   123          gt   abc    It s even significantly faster  almost 40  with the bang method  than the top answer  Here s the result of the same benchmark                        user     system      total        real chomp            0 949823   0 001025   0 950848    0 951941  range            1 874237   0 001472   1 875709    1 876820  delete suffix    0 721699   0 000945   0 722644    0 723410  delete suffix    0 650042   0 000714   0 650756    0 651332    I hope this is useful - note the method doesn t currently accept a regex so if you don t know the suffix it s not viable for the time being  However  as the accepted answer  update  at the time of writing  dictates the same  I thought this might be useful to some people

User · Answer

I would suggest chop  I think it has been mentioned in one of the comments but without links or explanations so here s why I think it s better   It simply removes the last character from a string and you don t have to specify any values for that to happen    If you need to remove more than one character then chomp is your best bet  This is what the ruby docs have to say about chop      Returns a new String with the last character removed  If the string   ends with  r n  both characters are removed  Applying chop to an empty   string returns an empty string  String chomp is often a safer   alternative  as it leaves the string unchanged if it doesn   t end in a   record separator    Although this is used mostly to remove separators such as  r n I ve used it to remove the last character from a simple string  for example the s to make the word singular

User · Answer

If the characters you want to remove are always the same characters  then consider chomp    abc123  chomp  123          gt   abc    The advantages of chomp are  no counting  and the code more clearly communicates what it is doing   With no arguments  chomp removes the DOS or Unix line ending  if either is present    abc n  chomp          gt   abc   abc r n  chomp        gt   abc      From the comments  there was a question of the speed of using  chomp versus using a range  Here is a benchmark comparing the two   require  benchmark   S    asdfghjkl  SL   S length T   10 000 A   1 000 times map    n     n   S      GC disable  Benchmark bmbm do  x    x report  chomp     T times   A each    s  s chomp S          x report  range     T times   A each    s  s 0   -SL        end   Benchmark Results  using CRuby 2 13p242    Rehearsal ----------------------------------------- chomp   1 540000   0 040000   1 580000    1 587908  range   1 810000   0 200000   2 010000    2 011846  -------------------------------- total  3 590000sec              user     system      total        real chomp   1 550000   0 070000   1 620000    1 610362  range   1 970000   0 170000   2 140000    2 146682    So chomp is faster than using a range  by  22

User · Answer

Check out the slice   method   http   ruby-doc org core-2 5 0 String html method-i-slice

User · Answer

irb gt   now is the time  0   -4    gt   now is the

User · Answer

Using regex   str    string  n   2   to remove last n characters  str   A    str size-n        gt   stri

User · Answer

if you are using rails  try     my string  last 2      gt   ng     EDITED    To get the string WITHOUT the last 2 chars   n    my string  size  my string  0  n-3      gt   my stri    Note  the last string char is at n-1  So  to remove the last 2  we use n-3

User · Answer

Dropping the last n characters is the same as keeping the first length - n characters   Active Support includes String first and String last methods which provide a convenient way to keep or drop the first last n characters   require  active support core ext string access    foobarbaz  first 3       gt   foo   foobarbaz  first -3      gt   foobar   foobarbaz  last 3        gt   baz   foobarbaz  last -3       gt   barbaz

[ruby] Ruby, remove last N characters from a string?

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