bar_chart or pie_chart kind (see Defining variables). The variable’s value stays a table — the chart only changes how that table is shown.
Bar charts
Abar_chart plots a table’s values as bars. Each series is one column or one row of the table, drawn as a set of bars, and the table’s shape is what decides how many series there are.
You configure:
- Series orientation — whether one series is a column or a row of the table. See Series orientation.
- Stacking — whether the series are drawn side by side or stacked into a single bar per group.
- Axis title — the label shown under the x-axis.
- Labels — whether the x-axis labels are a running number or the table’s first series. See X-axis labels.
- Series format — for each series, a name, a kind, and a format. The name labels that series in the legend; the kind and format apply to its values, the same scalar formatting a column uses.
Series orientation
The orientation setting says what one series is. Under column series, each column of the table is plotted as a series and each row is an x-axis category. Under row series, each row is plotted and each column is a category. Column series are the common case, because that is how most tables are shaped. An amortization schedule, or acolumns slice of one, has a period per row and a measure per column, so a schedule sliced to a payment column and a balance column, plotted by column, is two series with one x-axis category per period.
Choose row series only for a table laid out the other way: one row per measure, one column per period.
X-axis labels
The x-axis labels come from a running number or from the table’s first series. When the labels are a running number, they are integers counting up from a starting number you set, and every series in the table is plotted. When the labels come from the first series, you build the table with a series of label values in front — a column of dates, or of period names — and the chart draws the axis from that series instead of plotting it. The labels take their kind and format from it, so adate series gives an axis of dates. Where a label value is empty, the axis falls back to a positional name for that category, Row 3 under column series or Column 3 under row series, numbered from the same starting number.
Pie charts
Apie_chart plots one series as slices of a whole.
A pie plots a single row. Give it a flat list of values, or a table of one row. Where the table has more than one row, only the first is plotted.
You configure:
- Slice names — a label per slice, paired with the values in order. Where a name is missing or empty, that slice reads
Slice 3. - Kind and format — the scalar kind and format applied to slice values. Unlike a bar chart, which formats each series separately, a pie takes one setting for every slice.
Charting dates and durations
A chart series and a pie slice take the same kinds a column does, the four time kinds included, and the axis labels, tooltips, and legend format through whichever token you give them. A pie of durations — time spent per activity, as proportions of a whole — is the everyday case. Plotting instants works too, though a bar’s height is then measured from 1970, which rarely makes a readable chart. Dates are usually more useful as the axis labels than as the bars.Mixed units in a chart
When the column behind a chart holds values in different units of the same dimension —3 ft, 4 in, and 5 yd in one column, say — the chart draws every bar or slice to a single common unit, so their sizes are proportioned honestly rather than taken from the raw numbers. Each label and tooltip still shows the value’s original unit, so the 4 in bar reads 4 in even though it is drawn on a ft axis. The common unit is the first cell’s unit, and a pie chart’s percentages are taken from those common-unit magnitudes. This needs no authoring action — a mixed-unit column charts correctly on its own.
To pin the axis to a particular unit instead of the first cell’s, cast the column to that unit in the chart variable’s equation; casting converts the data, so the labels then show the unit you chose.
If a column instead mixes different dimensions — a length and a mass, say — there is no common axis to draw against, so the chart shows a short message naming the conflicting unit types rather than a misleading chart. Keep a chart’s column to a single dimension.