[feature] addcol-histogram #2052

visidata/features/addcol_histogram.py

@@ -0,0 +1,34 @@
+from visidata import vd, Column, Sheet, asyncthread, Progress
+
+
+class HistogramColumn(Column):
+    def calcValue(col, row):
+        histogram = col.sheet.options.disp_histogram
+        histolen = (col.width-2)*col.sourceCol.getTypedValue(row)//(col.sourceCol.largest-col.sourceCol.smallest)
+        return histogram*histolen
+
+
+@Sheet.api
+def addcol_histogram(sheet, col):  #2052
+    newcol = HistogramColumn(col.name+'_histogram', sourceCol=col)
+    col.smallest = None
+    col.largest = None
+    sheet.calc_histogram_bounds(col)
+    return newcol
+
+
+@Sheet.api
+@asyncthread
+def calc_histogram_bounds(sheet, col):
+    for row in Progress(sheet.rows):
+        v = col.getTypedValue(row)
+        if col.smallest is None or v < col.smallest:
+            col.smallest = v
+        if col.largest is None or v > col.largest:
+            col.largest = v
+
+
+Sheet.addCommand('', 'addcol-histogram', 'addColumnAtCursor(addcol_histogram(cursorCol))', 'add column with histogram of current column')
+
+
+vd.addMenuItems('Column > Add column > histogram')