count appearance of substringss count(sub [start[end]]begins/ends with substrings startswith(sub[start[end]] endswith(sub[start[end]]all capital/lowercase letterss upper( lower(remove whitespaces strip([chars]split at substrings split([sub [,maxsplit]]find position of substrings index(sub[start[end]]replace substrings replace(oldnew[count]more methodshelp(strdir(strmember of the helmholtz association slide