How to Trim Whitespace from a String

How to remove all white space from the beginning or end of a string?

String.Trim() returns a string which equals the input string with all white-spaces trimmed from start and end:

"   A String   ".Trim() -> "A String"

String.TrimStart() returns a string with white-spaces trimmed from the start:

"   A String   ".TrimStart() -> "A String   "

String.TrimEnd() returns a string with white-spaces trimmed from the end:

"   A String   ".TrimEnd() -> "   A String"

None of the methods modify the original string object.

(In some implementations at least, if there are no white-spaces to be trimmed, you get back the same string object you started with:

csharp> string a = "a";
csharp> string trimmed = a.Trim();
csharp> (object) a == (object) trimmed;
returns true

I don't know whether this is guaranteed by the language.)

How to remove whitespace from a string in typescript?

Problem

The trim() method removes whitespace from both sides of a string.

Source

Solution

You can use a Javascript replace method to remove white space like

"hello world".replace(/\s/g, "");

Example

var out = "hello world".replace(/\s/g, "");console.log(out);

How to remove a white space at the end of a string in java?

If you just want to trim whitespace at the end, use String#replaceAll() with an appropriate regex:

String input = " XXXX ";
String output = input.replaceAll("\\s+$", "");
System.out.println("***" + input + "***");   // *** XXXX ***
System.out.println("***" + output + "***");  // *** XXXX***

If you really want to replace just one whitespace character at the end, then replace on \s$ instead of \s+$.

How to remove the white space at the start of the string

This is what you want:

function ltrim(str) {
  if(!str) return str;
  return str.replace(/^\s+/g, '');
}

Also for ordinary trim in IE8+:

function trimStr(str) {
  if(!str) return str;
  return str.replace(/^\s+|\s+$/g, '');
}

And for trimming the right side:

function rtrim(str) {
  if(!str) return str;
  return str.replace(/\s+$/g, '');
}

Or as polyfill:

// for IE8
if (!String.prototype.trim)
{
    String.prototype.trim = function ()
    {
        // return this.replace(/^\s+|\s+$/g, '');
        return this.replace(/^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g, '');
    };
}

if (!String.prototype.trimStart)
{
    String.prototype.trimStart = function ()
    {
        // return this.replace(/^\s+/g, '');
        return this.replace(/^[\s\uFEFF\xA0]+/g, '');
    };
}

if (!String.prototype.trimEnd)
{
    String.prototype.trimEnd = function ()
    {
        // return this.replace(/\s+$/g, '');
        return this.replace(/[\s\uFEFF\xA0]+$/g, '');
    };
}

Note:

\s: includes spaces, tabs \t, newlines \n and few other rare characters, such as \v, \f and \r.

\uFEFF: Unicode Character 'ZERO WIDTH NO-BREAK SPACE' (U+FEFF)

\xA0: ASCII 0xA0 (160: non-breaking space) is not recognised as a space character

Remove all whitespace in a string

If you want to remove leading and ending spaces, use str.strip():

>>> "  hello  apple  ".strip()
'hello  apple'

If you want to remove all space characters, use str.replace() (NB this only removes the “normal” ASCII space character ' ' U+0020 but not any other whitespace):

>>> "  hello  apple  ".replace(" ", "")
'helloapple'

If you want to remove duplicated spaces, use str.split() followed by str.join():

>>> " ".join("  hello  apple  ".split())
'hello apple'

How do I trim leading/trailing whitespace in a standard way?

If you can modify the string:

// Note: This function returns a pointer to a substring of the original string.
// If the given string was allocated dynamically, the caller must not overwrite
// that pointer with the returned value, since the original pointer must be
// deallocated using the same allocator with which it was allocated.  The return
// value must NOT be deallocated using free() etc.
char *trimwhitespace(char *str)
{
  char *end;

  // Trim leading space
  while(isspace((unsigned char)*str)) str++;

  if(*str == 0)  // All spaces?
    return str;

  // Trim trailing space
  end = str + strlen(str) - 1;
  while(end > str && isspace((unsigned char)*end)) end--;

  // Write new null terminator character
  end[1] = '\0';

  return str;
}

If you can't modify the string, then you can use basically the same method:

// Stores the trimmed input string into the given output buffer, which must be
// large enough to store the result.  If it is too small, the output is
// truncated.
size_t trimwhitespace(char *out, size_t len, const char *str)
{
  if(len == 0)
    return 0;

  const char *end;
  size_t out_size;

  // Trim leading space
  while(isspace((unsigned char)*str)) str++;

  if(*str == 0)  // All spaces?
  {
    *out = 0;
    return 1;
  }

  // Trim trailing space
  end = str + strlen(str) - 1;
  while(end > str && isspace((unsigned char)*end)) end--;
  end++;

  // Set output size to minimum of trimmed string length and buffer size minus 1
  out_size = (end - str) < len-1 ? (end - str) : len-1;

  // Copy trimmed string and add null terminator
  memcpy(out, str, out_size);
  out[out_size] = 0;

  return out_size;
}

Remove all white space from string JavaScript

Use this:

str.replace(/\s+/g, '');

Instead of this:

str.trim()

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