docs/latex/wx/arrstrng.tex

   1 \section{\class{wxArrayString}}\label{wxarraystring}
   2
   3 wxArrayString is an efficient container for storing
   4 \helpref{wxString}{wxstring} objects. It has the same features as all
   5 \helpref{wxArray}{wxarray} classes, i.e. it dynamically expands when new items
   6 are added to it (so it is as easy to use as a linked list), but the access
   7 time to the elements is constant, instead of being linear in number of
   8 elements as in the case of linked lists. It is also very size efficient and
   9 doesn't take more space than a C array {\it wxString[]} type (wxArrayString
  10 uses its knowledge of internals of wxString class to achieve this).
  11
  12 This class is used in the same way as other dynamic \helpref{arrays}{wxarray},
  13 except that no {\it WX\_DEFINE\_ARRAY} declaration is needed for it. When a
  14 string is added or inserted in the array, a copy of the string is created, so
  15 the original string may be safely deleted (e.g. if it was a {\it char *}
  16 pointer the memory it was using can be freed immediately after this). In
  17 general, there is no need to worry about string memory deallocation when using
  18 this class - it will always free the memory it uses itself.
  19
  20 The references returned by \helpref{Item}{wxarraystringitem},
  21 \helpref{Last}{wxarraystringlast} or
  22 \helpref{operator[]}{wxarraystringoperatorindex} are not constant, so the
  23 array elements may be modified in place like this
  24
  25 \begin{verbatim}
  26     array.Last().MakeUpper();
  27 \end{verbatim}
  28
  29 There is also a varian of wxArrayString called wxSortedArrayString which has
  30 exactly the same methods as wxArrayString, but which always keeps the string
  31 in it in (alphabetical) order. wxSortedArrayString uses binary search in its
  32 \helpref{Index}{wxarraystringindex} function (insteadf of linear search for
  33 wxArrayString::Index) which makes it much more efficient if you add strings to
  34 the array rarely (because, of course, you have to pay for Index() efficiency
  35 by having Add() be slower) but search for them often. Several methods should
  36 not be used with sorted array (basicly, all which break the order of items)
  37 which is mentioned in their description.
  38
  39 Final word: none of the methods of wxArrayString is virtual including its
  40 destructor, so this class should not be used as a base class.
  41
  42 \wxheading{Derived from}
  43
  44 Although this is not true strictly speaking, this class may be considered as a
  45 specialization of \helpref{wxArray}{wxarray} class for the wxString member
  46 data: it is not implemented like this, but it does have all of the wxArray
  47 functions.
  48
  49 \wxheading{Include files}
  50
  51 <wx/string.h>
  52
  53 \wxheading{See also}
  54
  55 \helpref{wxArray}{wxarray}, \helpref{wxString}{wxstring}, \helpref{wxString overview}{wxstringoverview}
  56
  57 \latexignore{\rtfignore{\wxheading{Members}}}
  58
  59 \membersection{wxArrayString::wxArrayString}\label{wxarraystringctor}
  60
  61 \func{}{wxArrayString}{\void}
  62
  63 \func{}{wxArrayString}{\param{const wxArrayString\&}{ array}}
  64
  65 Default and copy constructors.
  66
  67 Note that when an array is assigned to a sorted array, its contents is
  68 automatically sorted during construction.
  69
  70 \membersection{wxArrayString::\destruct{wxArrayString}}\label{wxarraystringdtor}
  71
  72 \func{}{\destruct{wxArrayString}}{}
  73
  74 Destructor frees memory occupied by the array strings. For the performance
  75 reasons it is not virtual, so this class should not be derived from.
  76
  77 \membersection{wxArrayString::operator=}\label{wxarraystringoperatorassign}
  78
  79 \func{wxArrayString \&}{operator $=$}{\param{const wxArrayString\&}{ array}}
  80
  81 Assignment operator.
  82
  83 \membersection{wxArrayString::operator[]}\label{wxarraystringoperatorindex}
  84
  85 \func{wxString\&}{operator[]}{\param{size\_t }{nIndex}}
  86
  87 Return the array element at position {\it nIndex}. An assert failure will
  88 result from an attempt to access an element beyond the end of array in debug
  89 mode, but no check is done in release mode.
  90
  91 This is the operator version of \helpref{Item}{wxarraystringitem} method.
  92
  93 \membersection{wxArrayString::Add}\label{wxarraystringadd}
  94
  95 \func{size\_t}{Add}{\param{const wxString\& }{str}}
  96
  97 Appends a new item to the array and return the index of th new item in the
  98 array.
  99
 100 {\bf Warning:} For sorted arrays, the index of the inserted item will not be,
 101 in general, equal to \helpref{GetCount()}{wxarraystringgetcount} - 1 because
 102 the item is inserted at the correct position to keep the array sorted and not
 103 appended.
 104
 105 See also: \helpref{Insert}{wxarraystringinsert}
 106
 107 \membersection{wxArrayString::Alloc}\label{wxarraystringalloc}
 108
 109 \func{void}{Alloc}{\param{size\_t }{nCount}}
 110
 111 Preallocates enough memory to store {\it nCount} items. This function may be
 112 used to improve array class performance before adding a known number of items
 113 consecutively.
 114
 115 See also: \helpref{Dynamic array memory management}{wxarraymemorymanagement}
 116
 117 \membersection{wxArrayString::Clear}\label{wxarraystringclear}
 118
 119 \func{void}{Clear}{\void}
 120
 121 Clears the array contents and frees memory.
 122
 123 See also: \helpref{Empty}{wxarraystringempty}
 124
 125 \membersection{wxArrayString::Count}\label{wxarraystringcount}
 126
 127 \constfunc{size\_t}{Count}{\void}
 128
 129 Returns the number of items in the array. This function is deprecated and is
 130 for backwards compatibility only, please use
 131 \helpref{GetCount}{wxarraystringgetcount} instead.
 132
 133 \membersection{wxArrayString::Empty}\label{wxarraystringempty}
 134
 135 \func{void}{Empty}{\void}
 136
 137 Empties the array: after a call to this function
 138 \helpref{GetCount}{wxarraystringgetcount} will return $0$. However, this
 139 function does not free the memory used by the array and so should be used when
 140 the array is going to be reused for storing other strings. Otherwise, you
 141 should use \helpref{Clear}{wxarraystringclear} to empty the array and free
 142 memory.
 143
 144 \membersection{wxArrayString::GetCount}\label{wxarraystringgetcount}
 145
 146 \constfunc{size\_t}{GetCount}{\void}
 147
 148 Returns the number of items in the array.
 149
 150 \membersection{wxArrayString::Index}\label{wxarraystringindex}
 151
 152 \func{int}{Index}{\param{const char *}{ sz}, \param{bool}{ bCase = TRUE}, \param{bool}{ bFromEnd = FALSE}}
 153
 154 Search the element in the array, starting from the beginning if
 155 {\it bFromEnd} is FALSE or from end otherwise. If {\it bCase}, comparison is
 156 case sensitive (default), otherwise the case is ignored.
 157
 158 This function uses linear search for wxArrayString and binary search for
 159 wxSortedArrayString, but it ignores the {\it bCase} and {\it bFromEnd}
 160 parameters in the latter case.
 161
 162 Returns index of the first item matched or wxNOT\_FOUND if there is no match.
 163
 164 \membersection{wxArrayString::Insert}\label{wxarraystringinsert}
 165
 166 \func{void}{Insert}{\param{const wxString\& }{str}, \param{size\_t}{ nIndex}}
 167
 168 Insert a new element in the array before the position {\it nIndex}. Thus, for
 169 example, to insert the string in the beginning of the array you would write
 170
 171 \begin{verbatim}
 172 Insert("foo", 0);
 173 \end{verbatim}
 174
 175 If {\it nIndex} is equal to {\it GetCount() + 1} this function behaves as
 176 \helpref{Add}{wxarraystringadd}.
 177
 178 {\bf Warning:} this function should not be used with sorted array because it
 179 could break the order of items and, for example, subsequent calls to
 180 \helpref{Index()}{wxarraystringindex} would not work then!
 181
 182 \membersection{wxArrayString::IsEmpty}\label{wxarraystringisempty}
 183
 184 \func{}{IsEmpty}{}
 185
 186 Returns TRUE if the array is empty, FALSE otherwise. This function returns the
 187 same result as {\it GetCount() == 0} but is probably easier to read.
 188
 189 \membersection{wxArrayString::Item}\label{wxarraystringitem}
 190
 191 \constfunc{wxString\&}{Item}{\param{size\_t }{nIndex}}
 192
 193 Return the array element at position {\it nIndex}. An assert failure will
 194 result from an attempt to access an element beyond the end of array in debug
 195 mode, but no check is done in release mode.
 196
 197 See also \helpref{operator[]}{wxarraystringoperatorindex} for the operator
 198 version.
 199
 200 \membersection{wxArrayString::Last}\label{wxarraystringlast}
 201
 202 \func{}{Last}{}
 203
 204 Returns the last element of the array. Attempt to access the last element of
 205 an empty array will result in assert failure in debug build, however no checks
 206 are done in release mode.
 207
 208 \membersection{wxArrayString::Remove (by value)}\label{wxarraystringremoveval}
 209
 210 \func{void}{Remove}{\param{const char *}{ sz}}
 211
 212 Removes the first item matching this value. An assert failure is provoked by
 213 an attempt to remove an element which does not exist in debug build.
 214
 215 See also: \helpref{Index}{wxarraystringindex}, \helpref{Remove}{wxarraystringremove}
 216
 217 \membersection{wxArrayString::Remove (by index)}\label{wxarraystringremove}
 218
 219 \func{void}{Remove}{\param{size\_t }{nIndex}}
 220
 221 Removes the item at given position.
 222
 223 See also: \helpref{Remove}{wxarraystringremoveval}
 224
 225 \membersection{wxArrayString::Shrink}\label{wxarraystringshrink}
 226
 227 \func{void}{Shrink}{\void}
 228
 229 Releases the extra memory allocated by the array. This function is useful to
 230 minimize the array memory consumption.
 231
 232 See also: \helpref{Alloc}{wxarraystringalloc}, \helpref{Dynamic array memory management}{wxarraymemorymanagement}
 233
 234 \membersection{wxArrayString::Sort (alphabetically)}\label{wxarraystringsort}
 235
 236 \func{void}{Sort}{\param{bool}{ reverseOrder = FALSE}}
 237
 238 Sorts the array in alphabetical order or in reverse alphabetical order if
 239 {\it reverseOrder} is TRUE.
 240
 241 {\bf Warning:} this function should not be used with sorted array because it
 242 could break the order of items and, for example, subsequent calls to
 243 \helpref{Index()}{wxarraystringindex} would not work then!
 244
 245 See also: \helpref{Sort}{wxarraystringsortcallback}
 246
 247 \membersection{wxArrayString::Sort (user defined)}\label{wxarraystringsortcallback}
 248
 249 \func{void}{Sort}{\param{CompareFunction }{compareFunction}}
 250
 251 Sorts the array using the specified {\it compareFunction} for item comparison.
 252 {\it CompareFunction} is defined as a function taking two {\it const
 253 wxString\&} parameters and returning {\it int} value less than, equal to or
 254 greater than 0 if the first string is less than, equal to or greater than the
 255 second one.
 256
 257 \wxheading{Example}
 258
 259 The following example sorts strings by their length.
 260
 261 \begin{verbatim}
 262 static int CompareStringLen(const wxString& first, const wxString& second)
 263 {
 264     return first.length() - second.length();
 265 }
 266
 267 ...
 268
 269 wxArrayString array;
 270
 271 array.Add("one");
 272 array.Add("two");
 273 array.Add("three");
 274 array.Add("four");
 275
 276 array.Sort(CompareStringLen);
 277 \end{verbatim}
 278
 279 {\bf Warning:} this function should not be used with sorted array because it
 280 could break the order of items and, for example, subsequent calls to
 281 \helpref{Index()}{wxarraystringindex} would not work then!
 282
 283 See also: \helpref{Sort}{wxarraystringsort}
 284