How to Delete Special Characters

How to remove special characters from a string?

That depends on what you define as special characters, but try replaceAll(...):

String result = yourString.replaceAll("[-+.^:,]","");

Note that the ^ character must not be the first one in the list, since you'd then either have to escape it or it would mean "any but these characters".

Another note: the - character needs to be the first or last one on the list, otherwise you'd have to escape it or it would define a range ( e.g. :-, would mean "all characters in the range : to ,).

So, in order to keep consistency and not depend on character positioning, you might want to escape all those characters that have a special meaning in regular expressions (the following list is not complete, so be aware of other characters like (, {, $ etc.):

String result = yourString.replaceAll("[\\-\\+\\.\\^:,]","");

If you want to get rid of all punctuation and symbols, try this regex: \p{P}\p{S} (keep in mind that in Java strings you'd have to escape back slashes: "\\p{P}\\p{S}").

A third way could be something like this, if you can exactly define what should be left in your string:

String  result = yourString.replaceAll("[^\\w\\s]","");

This means: replace everything that is not a word character (a-z in any case, 0-9 or _) or whitespace.

Edit: please note that there are a couple of other patterns that might prove helpful. However, I can't explain them all, so have a look at the reference section of regular-expressions.info.

Here's less restrictive alternative to the "define allowed characters" approach, as suggested by Ray:

String  result = yourString.replaceAll("[^\\p{L}\\p{Z}]","");

The regex matches everything that is not a letter in any language and not a separator (whitespace, linebreak etc.). Note that you can't use [\P{L}\P{Z}] (upper case P means not having that property), since that would mean "everything that is not a letter or not whitespace", which almost matches everything, since letters are not whitespace and vice versa.

Additional information on Unicode

Some unicode characters seem to cause problems due to different possible ways to encode them (as a single code point or a combination of code points). Please refer to regular-expressions.info for more information.

How can I remove special characters from a list of elements in python?

Use the str.translate() method to apply the same translation table to all strings:

removetable = str.maketrans('', '', '@#%')
out_list = [s.translate(removetable) for s in my_list]

The str.maketrans() static method is a helpful tool to produce the translation map; the first two arguments are empty strings because you are not replacing characters, only removing. The third string holds all characters you want to remove.

Demo:

>>> my_list = ["on@3", "two#", "thre%e"]
>>> removetable = str.maketrans('', '', '@#%')
>>> [s.translate(removetable) for s in my_list]
['on3', 'two', 'three']

C remove special characters from string

I think the problem is you are using malloc which allocates memory from the heap and since you are calling this function again and again you are running out of memory.
To solve this issue you have to call the free() function on the pointer returned by your preprocessString function
In your main block

char *result=preprocessString(inputstring);
//Do whatever you want to do with this result
free(result);

How to remove all special characters in Linux text

Remove everything except the printable characters (character class [:print:]), with sed:

sed $'s/[^[:print:]\t]//g' file.txt

[:print:] includes:

• [:alnum:] (alpha-numerics)
• [:punct:] (punctuations)
• space

The ANSI C quoting ($'') is used for interpreting \t as literal tab inside $'' (in bash and alike).

Remove all special characters and case from string in bash

cat yourfile.txt | tr -dc '[:alnum:]\n\r' | tr '[:upper:]' '[:lower:]'

The first tr deletes special characters. d means delete, c means complement (invert the character set). So, -dc means delete all characters except those specified. The \n and \r are included to preserve linux or windows style newlines, which I assume you want.

The second one translates uppercase characters to lowercase.

Remove all special characters except space from a string using JavaScript

You should use the string replace function, with a single regex.
Assuming by special characters, you mean anything that's not letter, here is a solution:

const str = "abc's test#s";console.log(str.replace(/[^a-zA-Z ]/g, ""));

find . -name '*(1)' -exec rm {} +