bar_chart or pie_chart display type (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 row or one column 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 each series is a column or a row of the table. A schedule with a payment column and a balance column, plotted by column, becomes two series.
- 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 display type, and a format. The name labels that series in the legend; the display type and format apply to its values, the same scalar formatting a column uses.
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 display type and format from it, so a series typed as adate gives an axis of dates. Where a label value is empty, the axis falls back to a positional name such as Column 3, 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. - Display type and format — the scalar type 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 display types 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.