table: FilterBy: support filtering rows

Author: jedib0t

README.md

@@ -5,7 +5,6 @@
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-[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
 
 Utilities to prettify console output of tables, lists, progress bars, text, and more
 with a heavy emphasis on customization and flexibility.

table/EXAMPLES.md

@@ -310,6 +310,77 @@ to get:
 
 ---
 
+<details>
+<summary><strong>Filtering</strong></summary>
+
+Filtering can be done on one or more columns. All filters are applied with AND logic (all must match).
+Filters are applied before sorting.
+
+```golang
+    t.FilterBy([]table.FilterBy{
+        {Name: "Salary", Operator: table.GreaterThan, Value: 2000},
+        {Name: "First Name", Operator: table.Contains, Value: "on"},
+    })
+```
+
+The `Operator` field in `FilterBy` supports various filtering operators:
+- `Equal` / `NotEqual` - Exact match
+- `GreaterThan` / `GreaterThanOrEqual` - Numeric comparisons
+- `LessThan` / `LessThanOrEqual` - Numeric comparisons
+- `Contains` / `NotContains` - String search
+- `StartsWith` / `EndsWith` - String prefix/suffix matching
+- `RegexMatch` / `RegexNotMatch` - Regular expression matching
+
+You can make string comparisons case-insensitive by setting `IgnoreCase: true`:
+```golang
+    t.FilterBy([]table.FilterBy{
+        {Name: "First Name", Operator: table.Equal, Value: "JON", IgnoreCase: true},
+    })
+```
+
+For advanced filtering requirements, you can provide a custom filter function:
+```golang
+    t.FilterBy([]table.FilterBy{
+        {
+            Number: 2,
+            CustomFilter: func(cellValue string) bool {
+                // Custom logic: include rows where first name length > 3
+                return len(cellValue) > 3
+            },
+        },
+    })
+```
+
+Example: Filter by salary and name
+```golang
+    t := table.NewWriter()
+    t.AppendHeader(table.Row{"#", "First Name", "Last Name", "Salary"})
+    t.AppendRows([]table.Row{
+        {1, "Arya", "Stark", 3000},
+        {20, "Jon", "Snow", 2000},
+        {300, "Tyrion", "Lannister", 5000},
+        {400, "Sansa", "Stark", 2500},
+    })
+    t.FilterBy([]table.FilterBy{
+        {Number: 4, Operator: table.GreaterThan, Value: 2000},
+        {Number: 3, Operator: table.Contains, Value: "Stark"},
+    })
+    t.Render()
+```
+to get:
+```
++-----+------------+-----------+--------+
+|   # | FIRST NAME | LAST NAME | SALARY |
++-----+------------+-----------+--------+
+|   1 | Arya       | Stark     |   3000 |
+| 400 | Sansa      | Stark     |   2500 |
++-----+------------+-----------+--------+
+```
+
+</details>
+
+---
+
 <details>
 <summary><strong>Sorting</strong></summary>
 

table/README.md

@@ -76,11 +76,19 @@ If you want very specific examples, look at the [EXAMPLES.md](EXAMPLES.md) file.
 
 ### Sorting & Filtering
 
-  - Sort by one or more Columns (`SortBy`)
+  - **Sorting**
+    - Sort by one or more Columns (`SortBy`)
     - Multiple column sorting support
-    - Various sort modes: alphabetical, numeric, alphanumeric, numeric-alpha
+    - Various sort modes: Alphabetical, Numeric, Alpha-numeric, Numeric-alpha
     - Case-insensitive sorting option (`IgnoreCase`)
     - Custom sorting functions (`CustomLess`) for advanced sorting logic
+  - **Filtering**
+    - Filter by one or more Columns (`FilterBy`)
+    - Multiple filters with AND logic (all must match)
+    - Various filter operators: Equal, NotEqual, GreaterThan, LessThan, Contains, StartsWith, EndsWith, RegexMatch
+    - Case-insensitive filtering option (`IgnoreCase`)
+    - Custom filter functions (`CustomFilter`) for advanced filtering logic
+    - Filters are applied before sorting
   - Suppress/hide columns with no content (`SuppressEmptyColumns`)
   - Hide specific columns (`ColumnConfig.Hidden`)
   - Suppress trailing spaces in the last column (`SuppressTrailingSpaces`)

table/filter.go

@@ -0,0 +1,250 @@
+package table
+
+import (
+	"fmt"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+// FilterBy defines what to filter (Column Name or Number), how to filter (Operator),
+// and the value to compare against.
+type FilterBy struct {
+	// Name is the name of the Column as it appears in the first Header row.
+	// If a Header is not provided, or the name is not found in the header, this
+	// will not work.
+	Name string
+	// Number is the Column # from left. When specified, it overrides the Name
+	// property. If you know the exact Column number, use this instead of Name.
+	Number int
+
+	// Operator defines how to compare the column value against the Value.
+	Operator FilterOperator
+
+	// Value is the value to compare against. The type should match the expected
+	// comparison type (string for string operations, numeric for numeric operations).
+	// For Contains, StartsWith, EndsWith, and RegexMatch, Value should be a string.
+	// For numeric comparisons (Equal, NotEqual, GreaterThan, etc.), Value can be
+	// a number (int, float64) or a string representation of a number.
+	Value interface{}
+
+	// IgnoreCase makes string comparisons case-insensitive (only applies to
+	// string-based operators).
+	IgnoreCase bool
+
+	// CustomFilter is a function that can be used to filter rows in a custom
+	// manner. Note that:
+	// * This overrides and ignores the Operator, Value, and IgnoreCase settings
+	// * This is called after the column contents are converted to string form
+	// * This function is expected to return:
+	//   * true => include the row
+	//   * false => exclude the row
+	//
+	// Use this when the default filtering logic is not sufficient.
+	CustomFilter func(cellValue string) bool
+}
+
+// FilterOperator defines how to filter.
+type FilterOperator int
+
+const (
+	// Equal filters rows where the column value equals the Value.
+	Equal FilterOperator = iota
+	// NotEqual filters rows where the column value does not equal the Value.
+	NotEqual
+	// GreaterThan filters rows where the column value is greater than the Value.
+	GreaterThan
+	// GreaterThanOrEqual filters rows where the column value is greater than or equal to the Value.
+	GreaterThanOrEqual
+	// LessThan filters rows where the column value is less than the Value.
+	LessThan
+	// LessThanOrEqual filters rows where the column value is less than or equal to the Value.
+	LessThanOrEqual
+	// Contains filters rows where the column value contains the Value (string search).
+	Contains
+	// NotContains filters rows where the column value does not contain the Value (string search).
+	NotContains
+	// StartsWith filters rows where the column value starts with the Value.
+	StartsWith
+	// EndsWith filters rows where the column value ends with the Value.
+	EndsWith
+	// RegexMatch filters rows where the column value matches the Value as a regular expression.
+	RegexMatch
+	// RegexNotMatch filters rows where the column value does not match the Value as a regular expression.
+	RegexNotMatch
+)
+
+func (t *Table) parseFilterBy(filterBy []FilterBy) []FilterBy {
+	var resFilterBy []FilterBy
+	for _, filter := range filterBy {
+		colNum := 0
+		if filter.Number > 0 && filter.Number <= t.numColumns {
+			colNum = filter.Number
+		} else if filter.Name != "" && len(t.rowsHeaderRaw) > 0 {
+			// Parse from raw header rows
+			for idx, colName := range t.rowsHeaderRaw[0] {
+				if fmt.Sprint(colName) == filter.Name {
+					colNum = idx + 1
+					break
+				}
+			}
+		}
+		if colNum > 0 {
+			resFilterBy = append(resFilterBy, FilterBy{
+				Name:         filter.Name,
+				Number:       colNum,
+				Operator:     filter.Operator,
+				Value:        filter.Value,
+				IgnoreCase:   filter.IgnoreCase,
+				CustomFilter: filter.CustomFilter,
+			})
+		}
+	}
+	return resFilterBy
+}
+
+func (t *Table) matchesFiltersRaw(row Row, filters []FilterBy) bool {
+	// All filters must match (AND logic)
+	for _, filter := range filters {
+		if !t.matchesFilterRaw(row, filter) {
+			return false
+		}
+	}
+	return true
+}
+
+func (t *Table) matchesFilterRaw(row Row, filter FilterBy) bool {
+	colIdx := filter.Number - 1
+	if colIdx < 0 || colIdx >= len(row) {
+		return false
+	}
+
+	cellValue := row[colIdx]
+	cellValueStr := fmt.Sprint(cellValue)
+
+	// Use custom filter if provided
+	if filter.CustomFilter != nil {
+		return filter.CustomFilter(cellValueStr)
+	}
+
+	// Use operator-based filtering
+	return t.matchesOperator(cellValueStr, filter)
+}
+
+func (t *Table) matchesOperator(cellValue string, filter FilterBy) bool {
+	switch filter.Operator {
+	case Equal:
+		return t.compareEqual(cellValue, filter.Value, filter.IgnoreCase)
+	case NotEqual:
+		return !t.compareEqual(cellValue, filter.Value, filter.IgnoreCase)
+	case GreaterThan:
+		return t.compareNumeric(cellValue, filter.Value, func(a, b float64) bool { return a > b })
+	case GreaterThanOrEqual:
+		return t.compareNumeric(cellValue, filter.Value, func(a, b float64) bool { return a >= b })
+	case LessThan:
+		return t.compareNumeric(cellValue, filter.Value, func(a, b float64) bool { return a < b })
+	case LessThanOrEqual:
+		return t.compareNumeric(cellValue, filter.Value, func(a, b float64) bool { return a <= b })
+	case Contains:
+		return t.compareContains(cellValue, filter.Value, filter.IgnoreCase)
+	case NotContains:
+		return !t.compareContains(cellValue, filter.Value, filter.IgnoreCase)
+	case StartsWith:
+		return t.compareStartsWith(cellValue, filter.Value, filter.IgnoreCase)
+	case EndsWith:
+		return t.compareEndsWith(cellValue, filter.Value, filter.IgnoreCase)
+	case RegexMatch:
+		return t.compareRegexMatch(cellValue, filter.Value, filter.IgnoreCase)
+	case RegexNotMatch:
+		return !t.compareRegexMatch(cellValue, filter.Value, filter.IgnoreCase)
+	default:
+		return false
+	}
+}
+
+func (t *Table) compareEqual(cellValue string, filterValue interface{}, ignoreCase bool) bool {
+	filterStr := fmt.Sprint(filterValue)
+	if ignoreCase {
+		return strings.EqualFold(cellValue, filterStr)
+	}
+	return cellValue == filterStr
+}
+
+func (t *Table) compareNumeric(cellValue string, filterValue interface{}, compareFunc func(float64, float64) bool) bool {
+	cellNum, cellErr := strconv.ParseFloat(cellValue, 64)
+	if cellErr != nil {
+		return false
+	}
+
+	var filterNum float64
+	switch v := filterValue.(type) {
+	case int:
+		filterNum = float64(v)
+	case int64:
+		filterNum = float64(v)
+	case float64:
+		filterNum = v
+	case float32:
+		filterNum = float64(v)
+	case string:
+		var err error
+		filterNum, err = strconv.ParseFloat(v, 64)
+		if err != nil {
+			return false
+		}
+	default:
+		// Try to convert to string and parse
+		filterStr := fmt.Sprint(filterValue)
+		var err error
+		filterNum, err = strconv.ParseFloat(filterStr, 64)
+		if err != nil {
+			return false
+		}
+	}
+
+	return compareFunc(cellNum, filterNum)
+}
+
+func (t *Table) compareContains(cellValue string, filterValue interface{}, ignoreCase bool) bool {
+	filterStr := fmt.Sprint(filterValue)
+	if ignoreCase {
+		return strings.Contains(strings.ToLower(cellValue), strings.ToLower(filterStr))
+	}
+	return strings.Contains(cellValue, filterStr)
+}
+
+func (t *Table) compareStartsWith(cellValue string, filterValue interface{}, ignoreCase bool) bool {
+	filterStr := fmt.Sprint(filterValue)
+	if ignoreCase {
+		return strings.HasPrefix(strings.ToLower(cellValue), strings.ToLower(filterStr))
+	}
+	return strings.HasPrefix(cellValue, filterStr)
+}
+
+func (t *Table) compareEndsWith(cellValue string, filterValue interface{}, ignoreCase bool) bool {
+	filterStr := fmt.Sprint(filterValue)
+	if ignoreCase {
+		return strings.HasSuffix(strings.ToLower(cellValue), strings.ToLower(filterStr))
+	}
+	return strings.HasSuffix(cellValue, filterStr)
+}
+
+func (t *Table) compareRegexMatch(cellValue string, filterValue interface{}, ignoreCase bool) bool {
+	filterStr := fmt.Sprint(filterValue)
+
+	// Compile the regex pattern
+	var pattern *regexp.Regexp
+	var err error
+	if ignoreCase {
+		pattern, err = regexp.Compile("(?i)" + filterStr)
+	} else {
+		pattern, err = regexp.Compile(filterStr)
+	}
+
+	if err != nil {
+		// If regex compilation fails, fall back to simple string matching
+		return t.compareEqual(cellValue, filterValue, ignoreCase)
+	}
+
+	return pattern.MatchString(cellValue)
+}