--- title: "Item" language: "en" type: "Symbol" summary: "Item[expr, options] represents an item within constructs such as Grid, Overlay, and Manipulate that displays with expr as the content, and with the specified options applied to the region containing expr." keywords: - item - grid item - grid cell - menu item - tab - TableItem canonical_url: "https://reference.wolfram.com/language/ref/Item.html" source: "Wolfram Language Documentation" related_guides: - title: "Grids & Tables" link: "https://reference.wolfram.com/language/guide/GridsAndTables.en.md" - title: "User Interface Structuring & Layout" link: "https://reference.wolfram.com/language/guide/UserInterfaceStructuringAndLayout.en.md" - title: "Options & Styling for Interactive Manipulation" link: "https://reference.wolfram.com/language/guide/OptionsAndStylingForInteractiveManipulation.en.md" - title: "Automated Reports" link: "https://reference.wolfram.com/language/guide/AutomatedReports.en.md" - title: "Creating Form Interfaces & Apps" link: "https://reference.wolfram.com/language/guide/CreatingFormsAndApps.en.md" related_functions: - title: "Pane" link: "https://reference.wolfram.com/language/ref/Pane.en.md" - title: "Style" link: "https://reference.wolfram.com/language/ref/Style.en.md" - title: "ItemSize" link: "https://reference.wolfram.com/language/ref/ItemSize.en.md" - title: "ItemStyle" link: "https://reference.wolfram.com/language/ref/ItemStyle.en.md" - title: "Spacings" link: "https://reference.wolfram.com/language/ref/Spacings.en.md" - title: "Inset" link: "https://reference.wolfram.com/language/ref/Inset.en.md" - title: "ImageSizeAction" link: "https://reference.wolfram.com/language/ref/ImageSizeAction.en.md" related_tutorials: - title: "Grids, Rows, and Columns" link: "https://reference.wolfram.com/language/tutorial/GridsRowsAndColumnsOverview.en.md" --- # Item Item[expr, options] represents an item within constructs such as Grid, Overlay, and Manipulate that displays with expr as the content, and with the specified options applied to the region containing expr. ## Details and Options * The following options can typically be given: | | | | | ----------------- | --------- | -------------------------------------------------------- | | Alignment | Automatic | alignment within the containing region | | Background | None | background color for the containing region | | BaseStyle | {} | base style specifications for the item | | ControlPlacement | Automatic | when used in Manipulate, where controls should be placed | | Frame | False | whether to include a frame around the containing region | | FrameStyle | Automatic | style for the frame | | ItemSize | Automatic | overall size allowed for the item | * ``Frame -> True`` specifies that a frame should be drawn around all edges of the item. * ``Frame -> {bottom, left, top, right}`` specifies what should be drawn on each edge of the item. * ``Item`` effectively modifies the properties of a parent function which supports ``Item``. If ``Item`` is not used inside of a function that supports it, the properties specified by ``Item`` will not be visible. ## Examples (18) ### Basic Examples (2) Put a frame around the first element in a grid: ```wl In[1]:= Grid[{{Item[a, Frame -> True], b}, {c, d}}] Out[1]= | | | | - | - | | a | b | | c | d | ``` --- Draw the first element of the grid with a red background: ```wl In[1]:= Grid[{{Item[a, Background -> Red], b}, {c, d}}] Out[1]= | | | | - | - | | a | b | | c | d | ``` ### Scope (3) Draw a frame on certain faces of the item: ```wl In[1]:= Grid[{{a, b}, {c, Item[b, Frame -> {False, True, True, False}]}}] Out[1]= | | | | - | - | | a | b | | c | b | ``` --- Center an annotation of a ``Manipulate`` : ```wl In[1]:= Manipulate[x, Item["The Title", Alignment -> Center], {x, 0, 1}] Out[1]= DynamicModule[«7»] ``` --- Set alignments of individual objects in an ``Overlay`` : ```wl In[1]:= Overlay[{1111, Item[88, Alignment -> Right]}] Out[1]= 1111 ``` ### Generalizations & Extensions (3) ``Item`` will apply its options to an entire spanning region: ```wl In[1]:= Grid[{{Item[a, Background -> Red], SpanFromLeft}, {c, d}}] Out[1]= | | | | - | - | | a | | | c | d | ``` --- ``Item`` also works in constructs that are implemented using ``Grid``, such as ``MatrixForm`` : ```wl In[1]:= MatrixForm[{{a, b}, {Item[c, Background -> Red], d}}] Out[1]//MatrixForm= (⁠| | | | - | - | | a | b | | c | d |⁠) ``` Also ``TableForm`` : ```wl In[2]:= TableForm[{{a, b}, {Item[c, Background -> Red], d}}] Out[2]//TableForm= | | | | :- | :- | | a | b | | c | d | ``` --- Options that are irrelevant to the parent of the ``Item`` are ignored: ```wl In[1]:= Overlay[{aaaaa, Item[b, Frame -> True]}] Out[1]= aaaaa ``` ### Options (7) #### Alignment (1) Change the alignment for a single item: ```wl In[1]:= Column[{"a", Item["b", Alignment -> Right], "cdefghijkl"}] Out[1]= "a" "b" "cdefghijkl" ``` #### Background (1) Change the background for a single item: ```wl In[1]:= Grid[{{a, b, c}, {Item[d, Background -> LightBlue], e, f}, {g, h, i}}, Background -> {{{Pink, White}}, None}] Out[1]= | | | | | - | - | - | | a | b | c | | d | e | f | | g | h | i | ``` #### ControlPlacement (1) Individually control the placement of an annotation: ```wl In[1]:= Manipulate[Expand[(a + b) ^ n], {n, 1, 20, 1}, Item["Polynomial of degree n", ControlPlacement -> Left]] Out[1]= DynamicModule[«7»] ``` #### Frame (2) Change the frame of a single item: ```wl In[1]:= Grid[{{a, b, c}, {d, Item[e, Frame -> True], f}, {g, h, i}}] Out[1]= | | | | | - | - | - | | a | b | c | | d | e | f | | g | h | i | ``` --- Remove the frame of a single item: ```wl In[1]:= Grid[{{a, b, c}, {d, Item[e, Frame -> None], f}, {g, h, i}}, Dividers -> All] Out[1]= | | | | | - | - | - | | a | b | c | | d | e | f | | g | h | i | ``` #### FrameStyle (1) Change the frame style of a single item: ```wl In[1]:= Grid[{{a, b, c}, {d, Item[e, FrameStyle -> AbsoluteThickness[3]], f}, {g, h, i}}, Dividers -> All, FrameStyle -> Directive[Red, AbsoluteThickness[2]]] Out[1]= | | | | | - | - | - | | a | b | c | | d | e | f | | g | h | i | ``` #### ItemSize (1) Change the size of a single item: ```wl In[1]:= Grid[{{a, b, c}, {d, Item[e, ItemSize -> {4, 4}], f}, {g, h, i}}, ItemSize -> {1, 1}, Alignment -> {Center, Center}, Background -> {{{Pink, White}}, {{LightBlue, White}}}] Out[1]= | | | | | - | - | - | | a | b | c | | d | e | f | | g | h | i | ``` ### Possible Issues (2) If ``Item`` is not the top-most item in the child of a function that supports ``Item``, it will not work: ```wl In[1]:= Grid[{{DynamicModule[{x = 1}, Item[x, Background -> LightGreen]]}}, Frame -> True] Out[1]= DynamicModule[«3»] ``` In most cases, it is easy to move ``Item`` to be the top-most child: ```wl In[2]:= Grid[{{Item[DynamicModule[{x = 1}, x], Background -> LightGreen]}}, Frame -> True] Out[2]= DynamicModule[«3»] ``` --- The background of an ``Item`` can blend with the ambient background color: ```wl In[1]:= Style[Grid[{{a, b}, {Item[c, Background -> Directive[Yellow, Opacity[.5]]], d}}], Background -> Pink] Out[1]= | | | | - | - | | a | b | | c | d | ``` However, the background does not blend with a background specified directly to the parent ``Grid`` : ```wl In[2]:= Grid[{{a, b}, {Item[c, Background -> Directive[Yellow, Opacity[.5]]], d}}, Background -> {Pink}] Out[2]= | | | | - | - | | a | b | | c | d | ``` ### Neat Examples (1) Highlight special elements of a large matrix to see its structure: ```wl In[1]:= a = {{1, 2}, {3, 4}}; Style[Grid[KroneckerProduct[IdentityMatrix[20], a]] /. {0 -> 0, x_ ? NumberQ -> Item[x, Background -> Orange]}, FontSize -> 5] Out[1]= | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | ... | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 2 | | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 4 | ``` ## See Also * [`Pane`](https://reference.wolfram.com/language/ref/Pane.en.md) * [`Style`](https://reference.wolfram.com/language/ref/Style.en.md) * [`ItemSize`](https://reference.wolfram.com/language/ref/ItemSize.en.md) * [`ItemStyle`](https://reference.wolfram.com/language/ref/ItemStyle.en.md) * [`Spacings`](https://reference.wolfram.com/language/ref/Spacings.en.md) * [`Inset`](https://reference.wolfram.com/language/ref/Inset.en.md) * [`ImageSizeAction`](https://reference.wolfram.com/language/ref/ImageSizeAction.en.md) ## Tech Notes * [Grids, Rows, and Columns](https://reference.wolfram.com/language/tutorial/GridsRowsAndColumnsOverview.en.md) ## Related Guides * [Grids & Tables](https://reference.wolfram.com/language/guide/GridsAndTables.en.md) * [User Interface Structuring & Layout](https://reference.wolfram.com/language/guide/UserInterfaceStructuringAndLayout.en.md) * [Options & Styling for Interactive Manipulation](https://reference.wolfram.com/language/guide/OptionsAndStylingForInteractiveManipulation.en.md) * [Automated Reports](https://reference.wolfram.com/language/guide/AutomatedReports.en.md) * [Creating Form Interfaces & Apps](https://reference.wolfram.com/language/guide/CreatingFormsAndApps.en.md) ## History * [Introduced in 2007 (6.0)](https://reference.wolfram.com/language/guide/SummaryOfNewFeaturesIn60.en.md) \| [Updated in 2010 (8.0)](https://reference.wolfram.com/language/guide/SummaryOfNewFeaturesIn80.en.md)