How can I set several Grids to have the same size?

Question

I generate different Grids with different columns. Automatically ImageSizes are fixed depending upon the data. So every Grid has a different size.

grid1=Grid[{{Item["Name", Frame -> True, Background -> LightBlue, Alignment -> Left], 
             Item["Branch", Frame -> True, Background -> LightBlue,Alignment -> Left], 
             Item["Section", Frame -> True, Background -> LightBlue,Alignment -> Left]},
            {"s", "IT", "A"}, 
            {"u", "IT", "A"}, 
            {"b","IT", "A"}, 
            {"b", "IT", "A"},
            {"b", "IT", "A"}}, Frame -> True
         ];

 grid2=Grid[{{Item["Name", Frame -> True, Background -> LightBlue, Alignment -> Left], 
             Item["Branch", Frame -> True, Background -> LightBlue,Alignment -> Left], 
             Item["Section", Frame -> True, Background -> LightBlue,Alignment -> Left]},
            {"subrahmanyam", "IT", "A"}, 
            {"Madhu", "IT", "A"}, 
            {"Kiran","IT", "A"}, 
            {"KalyanKumar", "IT", "A"},
            {"Pavan", "IT", "A"}}, Frame -> True
         ];
  grid3 = Grid[{{"Main", SpanFromLeft, SpanFromLeft, 
 SpanFromLeft}, {Item["Name", Frame -> True, 
  Background -> LightBlue, Alignment -> Left], 
 Item["Branch", Frame -> True, Background -> LightBlue, 
  Alignment -> Left], 
 Item["Section", Frame -> True, Background -> LightBlue, 
  Alignment -> Left], 
 Item["Section", Frame -> True, Background -> LightBlue, 
  Alignment -> Left]}, {"subrahmanyam", "IT", "A", "g"}, {"Madhu",
  "IT", "A"}, {"Kiran", "IT", "A"}, {"KalyanKumar", "IT", 
 "A"}, {"Pavan", "IT", "A"}}, Frame -> True, 
  ItemSize -> {{10, 7, 7, 7}, 1}];

 finalGrid=Grid[{{grid3},{grid1}, {grid2}, {grid1}, {grid2}, {grid1}, {grid2}}]

grid1Image=

grid2Image=

grid3Image=

finalImage=

If I place all the Grids columnwise within Grid, it doesn't look good.

So, I want to fix all the Grids with the same sizes. I tried various things, but nothing seems to work.

Can anybody help me?

Answer 1

Update 3: Dealing with subgrids with different number of columns:

The main difficulty with differing number of columns is that both Spacings and ItemSizes in the subgrids have to be taken into account to get the same total width for all the subgrids. With $m$ subgrids indexed $i=1, ..., m$, where subgrid $g_i$ has $n_i$ columns with column widths

$w_{i j}, \left(j = 1, ..., n_i \right) $

and spacings

$s_{i j}, \left(j = 1, ..., n_i +1 \right) $,

total width $\tau_i$ of subgrid $i$ is

$ \tau_i =\sum _{j=1}^{n_i} \left(s_{i j} + w_{i j} \right) + s_{i \left(n_i +1 \right)} $

In the following I added the following option settings to the three subgrids:

  (* grids 1 and 2 :*)
  Spacings -> 4, ItemSize -> {{15, {6}}, 1} 
  (* grid3 *)
  Spacings -> 3, ItemSize -> {{15, {4}}, 1}

With these settings:

 Grid[{{grid3}, {grid2}, {grid1}, {grid2}, {grid1}, {grid2}}]

gives

Note: using the following settings

 Spacings -> 4, ItemSize -> {{Scaled[6/24], {Scaled[3/24]}}, 1} (* grids 1 and 2*)
 Spacings -> 3, ItemSize -> {{Scaled[6/24], {Scaled[2/24]}}, 1}  (* grid 3 *)

produces the same result.

---

Original post: Subgrids with the same number of columns

You need to set common values for the column widths using ItemSize in the two grids.

 grid1 = Grid[{{Item["Name", Frame -> True, Background -> LightBlue,
     Alignment -> Left], 
    Item["Branch", Frame -> True, Background -> LightBlue, Alignment -> Left], 
    Item["Section", Frame -> True, Background -> LightBlue,  Alignment -> Left]},
     {"s", "IT", "A"}, {"u", "IT", "A"}, 
     {"b", "IT", "A"}, {"b", "IT", "A"}, {"b", "IT", "A"}}, Frame -> True, 
   ItemSize -> {{10, 7, 7}, 1}]; 
  grid2 = Grid[{{Item["Name", Frame -> True, Background -> LightBlue, 
    Alignment -> Left], 
   Item["Branch", Frame -> True, Background -> LightBlue,  Alignment -> Left], 
   Item["Section", Frame -> True, Background -> LightBlue,  Alignment -> Left]}, 
   {"subrahmanyam", "IT", "A"}, {"Madhu", "IT",  "A"}, 
   {"Kiran", "IT", "A"}, {"KalyanKumar", "IT", "A"}, 
   {"Pavan",  "IT", "A"}}, Frame -> True, 
   ItemSize -> {{10, 7, 7}, 1}]; 
  finalGrid = Grid[{{grid1}, {grid2}, {grid1}, {grid2}, {grid1}, {grid2}}]

Alternatively, you can use

   ItemSize -> {{Scaled[.1], Scaled[.05], Scaled[.05]}, 1} 

Note: If the length of the list colwidths in ItemSize->{colwidths, rowheights} is less than the number of columns in the grid, the remaining column widths will be determined by the default settings. If you put an extra layer of {} around colwidths, (that is,ItemSize->{{colwidths}, rowheights}) the column widths will be determined by cycling through the numbers provided in the list colwidths.

Update: Finer details of Grid option settings:

From Docs >> Grid >> Details and Options

Illustration with a simple example adapted from the documentation examples:

data = {{"first", 1, 2, 3, 4, 5},  {"second", 11, 5, 6, 4, 2},
  {"third", 111, 8, 9, 3, 3},   {"fourth", 1111, 10, 11, 2, 2}}; 

 Grid[Prepend[data, {"name", "a", "b", "c", "d", "e"}],
  Background -> {None, {Lighter[Yellow, .9], 
   {White, Lighter[Blend[{Blue, Green}], .8]}}},
 Dividers -> All,  Alignment -> {{Left, Right, {Left}}},
 ItemSize -> {{{7, 3, 5}}, 1}]

 Grid[Prepend[data, {"name", "a", "b", "c", "d", "e"}], Dividers -> All,
 Background -> {None, {Lighter[Yellow, .9], {White, 
     Lighter[Blend[{Blue, Green}], .8]}}},
 Alignment -> {{Left, Right, {Left}}},
 ItemSize -> {{10, 5, {2}}, 1}]

Further reading:

From Mathematica documentation pages:

Grid
ItemSize
Tutorial- Grids Rows and Columns

Related Q/As on Mathematica.SE:

Setting equal column widths in Grid
Setting row heights in Grid