add support for negative filters (-F field!=regex)

README.md

@@ -22,7 +22,7 @@ Operational Flags:
   -s, --separator string            Custom field separator
   -k, --sort-by int                 Sort by column (default: 1)
   -z, --fuzzy                       Use fuzzy search [experimental]
-  -F, --filter field=reg            Filter given field with regex, can be used multiple times
+  -F, --filter field[!]=reg         Filter given field with regex, can be used multiple times
   -T, --transpose-columns string    Transpose the speficied columns (separated by ,)
   -R, --regex-transposer /from/to/  Apply /search/replace/ regexp to fields given in -T
 

cfg/config.go

@@ -1,5 +1,5 @@
 /*
-Copyright © 2022-2024 Thomas von Dein
+Copyright © 2022-2025 Thomas von Dein
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -58,6 +58,11 @@ type Pattern struct {
 	Negate    bool
 }
 
+type Filter struct {
+	Regex  *regexp.Regexp
+	Negate bool
+}
+
 // internal config
 type Config struct {
 	Debug          bool
@@ -100,7 +105,7 @@ type Config struct {
 
 	// used for field filtering
 	Rawfilters []string
-	Filters    map[string]*regexp.Regexp
+	Filters    map[string]Filter //map[string]*regexp.Regexp
 
 	// -r <file>
 	InputFile string
@@ -270,12 +275,20 @@ func (conf *Config) PrepareModeFlags(flag Modeflag) {
 }
 
 func (conf *Config) PrepareFilters() error {
-	conf.Filters = make(map[string]*regexp.Regexp, len(conf.Rawfilters))
+	conf.Filters = make(map[string]Filter, len(conf.Rawfilters))
 
-	for _, filter := range conf.Rawfilters {
+	for _, rawfilter := range conf.Rawfilters {
-		parts := strings.Split(filter, "=")
+		filter := Filter{}
+
+		parts := strings.Split(rawfilter, "!=")
 		if len(parts) != MAXPARTS {
-			return errors.New("filter field and value must be separated by =")
+			parts = strings.Split(rawfilter, "=")
+
+			if len(parts) != MAXPARTS {
+				return errors.New("filter field and value must be separated by '=' or '!='")
+			}
+		} else {
+			filter.Negate = true
 		}
 
 		reg, err := regexp.Compile(parts[1])
@@ -284,7 +297,8 @@ func (conf *Config) PrepareFilters() error {
 				parts[0], err)
 		}
 
-		conf.Filters[strings.ToLower(strings.ToLower(parts[0]))] = reg
+		filter.Regex = reg
+		conf.Filters[strings.ToLower(parts[0])] = filter
 	}
 
 	return nil

cmd/root.go

@@ -1,5 +1,5 @@
 /*
-Copyright © 2022-2024 Thomas von Dein
+Copyright © 2022-2025 Thomas von Dein
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -190,7 +190,7 @@ func Execute() {
 
 	// filters
 	rootCmd.PersistentFlags().StringArrayVarP(&conf.Rawfilters,
-		"filter", "F", nil, "Filter by field (field=regexp)")
+		"filter", "F", nil, "Filter by field (field=regexp || field!=regexp)")
 	rootCmd.PersistentFlags().StringArrayVarP(&conf.Transposers,
 		"regex-transposer", "R", nil, "apply /search/replace/ regexp to fields given in -T")
 

cmd/tablizer.go

@@ -17,7 +17,7 @@ SYNOPSIS
           -s, --separator string            Custom field separator
           -k, --sort-by int|name            Sort by column (default: 1)
           -z, --fuzzy                       Use fuzzy search [experimental]
-          -F, --filter field=reg            Filter given field with regex, can be used multiple times
+          -F, --filter field[!]=reg         Filter given field with regex, can be used multiple times
           -T, --transpose-columns string    Transpose the speficied columns (separated by ,)
           -R, --regex-transposer /from/to/  Apply /search/replace/ regexp to fields given in -T
 
@@ -181,6 +181,10 @@ DESCRIPTION
     If you specify more than one filter, both filters have to match (AND
     operation).
 
+    These field filters can also be negated:
+
+        fieldname!=regexp
+
     If the option -v is specified, the filtering is inverted.
 
   COLUMNS
@@ -416,7 +420,7 @@ Operational Flags:
   -s, --separator string            Custom field separator
   -k, --sort-by int|name            Sort by column (default: 1)
   -z, --fuzzy                       Use fuzzy search [experimental]
-  -F, --filter field=reg            Filter given field with regex, can be used multiple times
+  -F, --filter field[!]=reg         Filter given field with regex, can be used multiple times
   -T, --transpose-columns string    Transpose the speficied columns (separated by ,)
   -R, --regex-transposer /from/to/  Apply /search/replace/ regexp to fields given in -T
 

lib/filter.go

@@ -1,5 +1,5 @@
 /*
-Copyright © 2022-2024 Thomas von Dein
+Copyright © 2022-2025 Thomas von Dein
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -86,15 +86,19 @@ func FilterByFields(conf cfg.Config, data *Tabdata) (*Tabdata, bool, error) {
 		keep := true
 
 		for idx, header := range data.headers {
-			if !Exists(conf.Filters, strings.ToLower(header)) {
+			lcheader := strings.ToLower(header)
+			if !Exists(conf.Filters, lcheader) {
 				// do not filter by unspecified field
 				continue
 			}
 
-			if !conf.Filters[strings.ToLower(header)].MatchString(row[idx]) {
+			match := conf.Filters[lcheader].Regex.MatchString(row[idx])
-				// there IS a filter, but it doesn't match
+			if conf.Filters[lcheader].Negate {
-				keep = false
+				match = !match
+			}
 
+			if !match {
+				keep = false
 				break
 			}
 		}

lib/filter_test.go

@@ -1,5 +1,5 @@
 /*
-Copyright © 2024 Thomas von Dein
+Copyright © 2024-2025 Thomas von Dein
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -98,6 +98,20 @@ func TestFilterByFields(t *testing.T) {
 			},
 		},
 
+		{
+			name:   "one-field-negative",
+			filter: []string{"one!=asd"},
+			expect: Tabdata{
+				headers: []string{
+					"ONE", "TWO", "THREE",
+				},
+				entries: [][]string{
+					{"19191", "EDD 1", "x"},
+					{"8d8", "AN 1", "y"},
+				},
+			},
+		},
+
 		{
 			name:   "one-field-inverted",
 			filter: []string{"one=19"},

tablizer.1

@@ -133,7 +133,7 @@
 .\" ========================================================================
 .\"
 .IX Title "TABLIZER 1"
-.TH TABLIZER 1 "2025-01-22" "1" "User Commands"
+.TH TABLIZER 1 "2025-01-30" "1" "User Commands"
 .\" For nroff, turn off justification.  Always turn off hyphenation; it makes
 .\" way too many mistakes in technical documents.
 .if n .ad l
@@ -155,7 +155,7 @@ tablizer \- Manipulate tabular output of other programs
 \&      \-s, \-\-separator string            Custom field separator
 \&      \-k, \-\-sort\-by int|name            Sort by column (default: 1)
 \&      \-z, \-\-fuzzy                       Use fuzzy search [experimental]
-\&      \-F, \-\-filter field=reg            Filter given field with regex, can be used multiple times
+\&      \-F, \-\-filter field[!]=reg         Filter given field with regex, can be used multiple times
 \&      \-T, \-\-transpose\-columns string    Transpose the speficied columns (separated by ,)
 \&      \-R, \-\-regex\-transposer /from/to/  Apply /search/replace/ regexp to fields given in \-T
 \&
@@ -340,6 +340,12 @@ Fieldnames (== columns headers) are case insensitive.
 If you specify more than one filter, both filters have to match (\s-1AND\s0
 operation).
 .PP
+These field filters can also be negated:
+.PP
+.Vb 1
+\&    fieldname!=regexp
+.Ve
+.PP
 If the option \fB\-v\fR is specified, the filtering is inverted.
 .SS "\s-1COLUMNS\s0"
 .IX Subsection "COLUMNS"

tablizer.pod

@@ -16,7 +16,7 @@ tablizer - Manipulate tabular output of other programs
       -s, --separator string            Custom field separator
       -k, --sort-by int|name            Sort by column (default: 1)
       -z, --fuzzy                       Use fuzzy search [experimental]
-      -F, --filter field=reg            Filter given field with regex, can be used multiple times
+      -F, --filter field[!]=reg         Filter given field with regex, can be used multiple times
       -T, --transpose-columns string    Transpose the speficied columns (separated by ,)
       -R, --regex-transposer /from/to/  Apply /search/replace/ regexp to fields given in -T
 
@@ -194,6 +194,10 @@ Fieldnames (== columns headers) are case insensitive.
 If you specify more than one filter, both filters have to match (AND
 operation).
 
+These field filters can also be negated:
+
+    fieldname!=regexp
+
 If the option B<-v> is specified, the filtering is inverted.