Column

C++ SDK API Documentation - Column

class Column : public AbstractColumn

Aspect that manages a column.

This class represents a column, i.e., (mathematically) a 1D vector of values with a header. It provides a public reading and (undo aware) writing interface as defined in AbstractColumn. A column can have one of currently three data types: double, QString, or QDateTime. The string representation of the values can differ depending on the mode of the column.

Column inherits from AbstractAspect and is intended to be a child of the corresponding Spreadsheet in the aspect hierarchy. Columns don’t have a view as they are intended to be displayed inside a spreadsheet.

type specific functions

virtual QIcon icon() const override

Return an icon to be used for decorating the views and spreadsheet column headers.

bool hasValues() const

return true if the column has at least one valid (not empty) value, false otherwise.

bool hasValueAt(int row) const

return true if the column has a valid value in the row \row.

virtual Properties properties() const override

Column::properties Returns the column properties of this curve (monoton increasing, monoton decreasing, … )

See also

AbstractColumn::properties

virtual QString textAt(int) const override

Return the content of row ‘row’.

Use this only when columnMode() is Text

virtual void setTextAt(int, const QString&) override

Set the content of row ‘row’.

Use this only when columnMode() is Text

virtual void replaceTexts(int, const QVector<QString>&) override

Replace a range of values.

Use this only when columnMode() is Text

virtual int dictionaryIndex(int row) const override

Return the position/index in the dictionary for the text value at.

Use this only when columnMode() is Text

Parameters:

row –

virtual QDate dateAt(int) const override

Return the date part of row ‘row’.

Use this only when columnMode() is DateTime, Month or Day

virtual void setDateAt(int, QDate) override

Set the content of row ‘row’.

Use this only when columnMode() is DateTime, Month or Day

virtual QTime timeAt(int) const override

Return the time part of row ‘row’.

Use this only when columnMode() is DateTime, Month or Day

virtual void setTimeAt(int, QTime) override

Set the content of row ‘row’.

Use this only when columnMode() is DateTime, Month or Day

virtual QDateTime dateTimeAt(int) const override

Return the QDateTime in row ‘row’.

Use this only when columnMode() is DateTime, Month or Day

virtual void setDateTimeAt(int, const QDateTime&) override

Set the content of row ‘row’.

Use this only when columnMode() is DateTime, Month or Day

virtual void replaceDateTimes(int, const QVector<QDateTime>&) override

Replace a range of values.

Use this only when columnMode() is DateTime, Month or Day

virtual double doubleAt(int) const override

Return the double value in row ‘row’.

Use this only when columnMode() is Numeric

virtual double valueAt(int) const override

Return the double value in row ‘row’.

virtual void setValueAt(int, double) override

Set the content of row ‘row’.

Use this only when columnMode() is Numeric

virtual void replaceValues(int, const QVector<double>&) override

Replace a range of values.

Use this only when columnMode() is Numeric

virtual int integerAt(int) const override

Return the int value in row ‘row’.

virtual void setIntegerAt(int, int) override

Set the content of row ‘row’.

Use this only when columnMode() is Integer

virtual void replaceInteger(int, const QVector<int>&) override

Replace a range of values.

Use this only when columnMode() is Integer

virtual qint64 bigIntAt(int) const override

Return the bigint value in row ‘row’.

virtual void setBigIntAt(int, qint64) override

Set the content of row ‘row’.

Use this only when columnMode() is BigInt

virtual void replaceBigInt(int, const QVector<qint64>&) override

Replace a range of values.

Use this only when columnMode() is BigInt

serialize/deserialize

virtual AbstractColumn::ColumnMode columnMode() const override

Return the column mode.

This function is mostly used by spreadsheets but can also be used by plots. The column mode specifies how to interpret the values in the column additional to the data type.

virtual AbstractColumn::PlotDesignation plotDesignation() const override

Return the column plot designation.

virtual bool isReadOnly() const override

Return whether the object is read-only.

virtual int rowCount() const override

Return the data vector size.

virtual int availableRowCount(int max = -1) const override

Return the number of available data rows.

This returns the number of rows that actually contain data. Rows beyond this can be masked etc. but should be ignored by filters, plots etc.

ColumnStringIO *asStringColumn() const

Return a wrapper column object used for String I/O.

virtual void save(QXmlStreamWriter*) const override

Save the column as XML.

virtual bool load(XmlStreamReader*, bool preview) override

Load the column from XML.

Formula related functions

void setFormula(const QString &formula, const QStringList &variableNames, const QVector<Column*> &columns, bool autoUpdate = false, bool autoResize = true)

Sets the formula used to generate column values.

QString formula() const

Returns the formula used to generate column values.

void clearFormula()

Clears the formula used to generate column values.

virtual void setFormula(const Interval<int>&, const QString&) override

Set a formula string for an interval of rows.

virtual void setFormula(int, const QString&) override

Overloaded function for convenience.

virtual void clearFormulas() override

Clear all formulas.

void updateFormula()

in case the cell values are calculated via a global column formula, updates the values on data changes in all the dependent changes in the “variable columns”.

IntervalAttribute related functions

virtual QString formula(int) const override

Return the formula associated with row ‘row’.

virtual QVector<Interval<int>> formulaIntervals() const override

Return the intervals that have associated formulas.

This can be used to make a list of formulas with their intervals. Here is some example code:

QStringList list;
QVector< Interval<int> > intervals = my_column.formulaIntervals();
foreach(Interval<int> interval, intervals)
    list << QString(interval.toString() + ": " + my_column.formula(interval.start()));

virtual double maximum(int count = 0) const override

calculates the maximal value in the column. for count = 0, the maximum of all elements is returned. for count > 0, the maximum of the first count elements is returned. for count < 0, the maximum of the last count elements is returned.

virtual double maximum(int startIndex, int endIndex) const override

Column::maximum Calculates the maximum value in the column between the startIndex and endIndex. If startIndex is greater than endIndex the indices are swapped startIndex endIndex.

virtual double minimum(int count = 0) const override

calculates the minimal value in the column. for count = 0, the minimum of all elements is returned. for count > 0, the minimum of the first count elements is returned. for count < 0, the minimum of the last count elements is returned.

virtual double minimum(int startIndex, int endIndex) const override

Column::minimum Calculates the minimum value in the column between the startIndex and endIndex, endIndex is excluded. If startIndex is greater than endIndex the indices are swapped startIndex endIndex.

virtual bool indicesMinMax(double v1, double v2, int &start, int &end) const override

Column::indicesMinMax.

Finds the minimal and maximal index which are between v1 and v2

Parameters:

• v1 –

• v2 –

• start –

• end –

Returns:

static int calculateMaxSteps(unsigned int value)

calculates log2(x)+1 for an integer value. Used in y(double x) to calculate the maximum steps source: https://stackoverflow.com/questions/11376288/fast-computing-of-log2-for-64-bit-integers source: https://graphics.stanford.edu/~seander/bithacks.html#IntegerLogLookup

Parameters:

value –

Returns:

returns calculated value

static int indexForValue(double x, QVector<double> &column, Properties properties = Properties::No)

Find index which corresponds to a x . In a vector of values When monotonic increasing or decreasing a different algorithm will be used, which needs less steps (mean) (log_2(rowCount)) to find the value.

Parameters:

x –

Returns:

-1 if index not found, otherwise the index

static int indexForValue(const double x, const QVector<QPointF> &column, Properties properties = Properties::No)

Find index which corresponds to a x . In a vector of values When monotonic increasing or decreasing a different algorithm will be used, which needs less steps (mean) (log_2(rowCount)) to find the value.

Parameters:

x –

Returns:

-1 if index not found, otherwise the index

static int indexForValue(double x, QVector<QLineF> &lines, Properties properties = Properties::No)

Find index which corresponds to a x . In a vector of values When monotonic increasing or decreasing a different algorithm will be used, which needs less steps (mean) (log_2(rowCount)) to find the value.

Parameters:

x –

Returns:

-1 if index not found, otherwise the index

Public Functions

void init()

Common part of ctors.

virtual QMenu *createContextMenu() override

Return a new context menu.

The caller takes ownership of the menu.

virtual void setColumnMode(AbstractColumn::ColumnMode) override

Set the column mode.

This sets the column mode and, if necessary, converts it to another datatype.

virtual bool copy(const AbstractColumn*) override

Copy another column of the same type.

This function will return false if the data type of ‘other’ is not the same as the type of ‘this’. Use a filter to convert a column to another type.

virtual bool copy(const AbstractColumn *source, int source_start, int dest_start, int num_rows) override

Copies a part of another column of the same type.

This function will return false if the data type of ‘other’ is not the same as the type of ‘this’.

Parameters:

• source – pointer to the column to copy

• source_start – first row to copy in the column to copy

• dest_start – first row to copy in

• num_rows – the number of rows to copy

virtual void setPlotDesignation(AbstractColumn::PlotDesignation) override

Set the column plot designation.

int width() const

Get width.

void setWidth(const int)

Set width.

virtual void clear(QUndoCommand *parent = nullptr) override

Clear the content of the column (data and formula definition)

struct FormulaData

struct RandomValuesData

template<typename T>
struct ValueLabel