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 wxChar *}
  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 variant 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 (instead 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 (basically, 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/arrstr.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 Default constructor.
  64
  65 \func{}{wxArrayString}{\param{const wxArrayString\&}{ array}}
  66
  67 Copy constructor. Note that when an array is assigned to a sorted array, its contents is
  68 automatically sorted during construction.
  69
  70 \func{}{wxArrayString}{\param{size\_t}{ sz}, \param{const wxChar**}{ arr}}
  71
  72 Constructor from a C string array. Pass a size {\it sz} and array {\it arr}.
  73
  74 \func{}{wxArrayString}{\param{size\_t}{ sz}, \param{const wxString*}{ arr}}
  75
  76 Constructor from a wxString array. Pass a size {\it sz} and array {\it arr}.
  77
  78 \membersection{wxArrayString::\destruct{wxArrayString}}\label{wxarraystringdtor}
  79
  80 \func{}{\destruct{wxArrayString}}{}
  81
  82 Destructor frees memory occupied by the array strings. For the performance
  83 reasons it is not virtual, so this class should not be derived from.
  84
  85 \membersection{wxArrayString::operator=}\label{wxarraystringoperatorassign}
  86
  87 \func{wxArrayString \&}{operator $=$}{\param{const wxArrayString\&}{ array}}
  88
  89 Assignment operator.
  90
  91 \membersection{wxArrayString::operator==}\label{wxarraystringoperatorequal}
  92
  93 \constfunc{bool}{operator $==$}{\param{const wxArrayString\&}{ array}}
  94
  95 Compares 2 arrays respecting the case. Returns true only if the arrays have
  96 the same number of elements and the same strings in the same order.
  97
  98 \membersection{wxArrayString::operator!=}\label{wxarraystringoperatornotequal}
  99
 100 \constfunc{bool}{operator $!=$}{\param{const wxArrayString\&}{ array}}
 101
 102 Compares 2 arrays respecting the case. Returns true if the arrays have
 103 different number of elements or if the elements don't match pairwise.
 104
 105 \membersection{wxArrayString::operator[]}\label{wxarraystringoperatorindex}
 106
 107 \func{wxString\&}{operator[]}{\param{size\_t }{nIndex}}
 108
 109 Return the array element at position {\it nIndex}. An assert failure will
 110 result from an attempt to access an element beyond the end of array in debug
 111 mode, but no check is done in release mode.
 112
 113 This is the operator version of \helpref{Item}{wxarraystringitem} method.
 114
 115 \membersection{wxArrayString::Add}\label{wxarraystringadd}
 116
 117 \func{size\_t}{Add}{\param{const wxString\& }{str}, \param{size\_t}{ copies = $1$}}
 118
 119 Appends the given number of {\it copies} of the new item {\it str} to the
 120 array and returns the index of the first new item in the array.
 121
 122 {\bf Warning:} For sorted arrays, the index of the inserted item will not be,
 123 in general, equal to \helpref{GetCount()}{wxarraystringgetcount} - 1 because
 124 the item is inserted at the correct position to keep the array sorted and not
 125 appended.
 126
 127 See also: \helpref{Insert}{wxarraystringinsert}
 128
 129 \membersection{wxArrayString::Alloc}\label{wxarraystringalloc}
 130
 131 \func{void}{Alloc}{\param{size\_t }{nCount}}
 132
 133 Preallocates enough memory to store {\it nCount} items. This function may be
 134 used to improve array class performance before adding a known number of items
 135 consecutively.
 136
 137 See also: \helpref{Dynamic array memory management}{wxarraymemorymanagement}
 138
 139 \membersection{wxArrayString::Clear}\label{wxarraystringclear}
 140
 141 \func{void}{Clear}{\void}
 142
 143 Clears the array contents and frees memory.
 144
 145 See also: \helpref{Empty}{wxarraystringempty}
 146
 147 \membersection{wxArrayString::Empty}\label{wxarraystringempty}
 148
 149 \func{void}{Empty}{\void}
 150
 151 Empties the array: after a call to this function
 152 \helpref{GetCount}{wxarraystringgetcount} will return $0$. However, this
 153 function does not free the memory used by the array and so should be used when
 154 the array is going to be reused for storing other strings. Otherwise, you
 155 should use \helpref{Clear}{wxarraystringclear} to empty the array and free
 156 memory.
 157
 158 \membersection{wxArrayString::GetCount}\label{wxarraystringgetcount}
 159
 160 \constfunc{size\_t}{GetCount}{\void}
 161
 162 Returns the number of items in the array.
 163
 164 \membersection{wxArrayString::Index}\label{wxarraystringindex}
 165
 166 \func{int}{Index}{\param{const wxChar *}{ sz}, \param{bool}{ bCase = true}, \param{bool}{ bFromEnd = false}}
 167
 168 Search the element in the array, starting from the beginning if
 169 {\it bFromEnd} is false or from end otherwise. If {\it bCase}, comparison is
 170 case sensitive (default), otherwise the case is ignored.
 171
 172 This function uses linear search for wxArrayString and binary search for
 173 wxSortedArrayString, but it ignores the {\it bCase} and {\it bFromEnd}
 174 parameters in the latter case.
 175
 176 Returns index of the first item matched or {\tt wxNOT\_FOUND} if there is no match.
 177
 178 \membersection{wxArrayString::Insert}\label{wxarraystringinsert}
 179
 180 \func{void}{Insert}{\param{const wxString\& }{str}, \param{size\_t}{ nIndex}, \param{size\_t }{copies = $1$}}
 181
 182 Insert the given number of {\it copies} of the new element in the array before the position {\it nIndex}. Thus, for
 183 example, to insert the string in the beginning of the array you would write
 184
 185 \begin{verbatim}
 186 Insert("foo", 0);
 187 \end{verbatim}
 188
 189 If {\it nIndex} is equal to {\it GetCount()} this function behaves as
 190 \helpref{Add}{wxarraystringadd}.
 191
 192 {\bf Warning:} this function should not be used with sorted arrays because it
 193 could break the order of items and, for example, subsequent calls to
 194 \helpref{Index()}{wxarraystringindex} would then not work!
 195
 196 \membersection{wxArrayString::IsEmpty}\label{wxarraystringisempty}
 197
 198 \func{bool}{IsEmpty}{}
 199
 200 Returns true if the array is empty, false otherwise. This function returns the
 201 same result as {\it GetCount() == 0} but is probably easier to read.
 202
 203 \membersection{wxArrayString::Item}\label{wxarraystringitem}
 204
 205 \constfunc{wxString\&}{Item}{\param{size\_t }{nIndex}}
 206
 207 Return the array element at position {\it nIndex}. An assert failure will
 208 result from an attempt to access an element beyond the end of array in debug
 209 mode, but no check is done in release mode.
 210
 211 See also \helpref{operator[]}{wxarraystringoperatorindex} for the operator
 212 version.
 213
 214 \membersection{wxArrayString::Last}\label{wxarraystringlast}
 215
 216 \func{wxString&}{Last}{}
 217
 218 Returns the last element of the array. Attempt to access the last element of
 219 an empty array will result in assert failure in debug build, however no checks
 220 are done in release mode.
 221
 222 \membersection{wxArrayString::Remove}\label{wxarraystringremove}
 223
 224 \func{void}{Remove}{\param{const wxChar *}{ sz}}
 225
 226 Removes the first item matching this value. An assert failure is provoked by
 227 an attempt to remove an element which does not exist in debug build.
 228
 229 See also: \helpref{Index}{wxarraystringindex}
 230
 231 \membersection{wxArrayString::RemoveAt}\label{wxarraystringremoveat}
 232
 233 \func{void}{RemoveAt}{\param{size\_t }{nIndex}, \param{size\_t }{count = $1$}}
 234
 235 Removes {\it count} items starting at position {\it nIndex} from the array.
 236
 237 \membersection{wxArrayString::Shrink}\label{wxarraystringshrink}
 238
 239 \func{void}{Shrink}{\void}
 240
 241 Releases the extra memory allocated by the array. This function is useful to
 242 minimize the array memory consumption.
 243
 244 See also: \helpref{Alloc}{wxarraystringalloc}, \helpref{Dynamic array memory management}{wxarraymemorymanagement}
 245
 246 \membersection{wxArrayString::Sort}\label{wxarraystringsort}
 247
 248 \func{void}{Sort}{\param{bool}{ reverseOrder = false}}
 249
 250 Sorts the array in alphabetical order or in reverse alphabetical order if
 251 {\it reverseOrder} is true. The sort is case-sensitive.
 252
 253 {\bf Warning:} this function should not be used with sorted array because it
 254 could break the order of items and, for example, subsequent calls to
 255 \helpref{Index()}{wxarraystringindex} would then not work!
 256
 257 \func{void}{Sort}{\param{CompareFunction }{compareFunction}}
 258
 259 Sorts the array using the specified {\it compareFunction} for item comparison.
 260 {\it CompareFunction} is defined as a function taking two {\it const
 261 wxString\&} parameters and returning an {\it int} value less than, equal to or
 262 greater than 0 if the first string is less than, equal to or greater than the
 263 second one.
 264
 265 \wxheading{Example}
 266
 267 The following example sorts strings by their length.
 268
 269 \begin{verbatim}
 270 static int CompareStringLen(const wxString& first, const wxString& second)
 271 {
 272     return first.length() - second.length();
 273 }
 274
 275 ...
 276
 277 wxArrayString array;
 278
 279 array.Add("one");
 280 array.Add("two");
 281 array.Add("three");
 282 array.Add("four");
 283
 284 array.Sort(CompareStringLen);
 285 \end{verbatim}
 286
 287 {\bf Warning:} this function should not be used with sorted array because it
 288 could break the order of items and, for example, subsequent calls to
 289 \helpref{Index()}{wxarraystringindex} would then not work!
 290