Say I have a string {100 aa bbc%j%b%wa ajjcj11j0%2wj fc} with a lot of undesired characters or spaces in it, for example: {" ", "%", "w", "j"}. I'd like to strip the string of these characters, with the provided example giving us the output string:
testString = "100 aa bbc%j%b%wa ajjcj11j0%2wj fc";
StringReplace[testString, {" ", "%", "w", "j"} -> ""]
out: "100aabbcbaac1102fc";
Now, say we don't have a convenient list of undesired characters / spaces / paragraph indicators / etc. Is there a way to select for certain characters instead of specifying that certain characters should be deleted (as in the example)?