csvlook: Add --max-rows, --max-columns and --max-column-width options

Author: James McKinney

CHANGELOG

@@ -22,6 +22,7 @@ Improvements:
 * csvjoin supports --no-header-row.
 * csvjson streams input and output if the --stream and --no-inference flags are set.
 * csvjson supports --snifflimit and --no-inference.
+* csvlook adds --max-rows, --max-columns and --max-column-width options.
 * csvlook supports --snifflimit and --no-inference.
 * csvsql supports custom SQLAlchemy dialects.
 * csvstat supports --names.

csvkit/utilities/csvlook.py

@@ -9,14 +9,20 @@ class CSVLook(CSVKitUtility):
     description = 'Render a CSV file in the console as a fixed-width table.'
 
     def add_arguments(self):
+        self.argparser.add_argument('--max-rows', dest='max_rows', type=int,
+                                    help='The maximum number of rows to display before truncating the data.')
+        self.argparser.add_argument('--max-columns', dest='max_columns', type=int,
+                                    help='The maximum number of columns to display before truncating the data.')
+        self.argparser.add_argument('--max-column-width', dest='max_column_width', type=int,
+                                    help='Truncate all columns to at most this width. The remainder will be replaced with ellipsis.')
         self.argparser.add_argument('-y', '--snifflimit', dest='sniff_limit', type=int,
                                     help='Limit CSV dialect sniffing to the specified number of bytes. Specify "0" to disable sniffing entirely.')
         self.argparser.add_argument('--no-inference', dest='no_inference', action='store_true',
                                     help='Disable type inference when parsing the input.')
 
     def main(self):
         table = agate.Table.from_csv(self.input_file, sniff_limit=self.args.sniff_limit, header=not self.args.no_header_row, column_types=self.get_column_types(), line_numbers=self.args.line_numbers, **self.reader_kwargs)
-        table.print_table(output=self.output_file, max_rows=None, max_columns=None, max_column_width=None)
+        table.print_table(output=self.output_file, max_rows=self.args.max_rows, max_columns=self.args.max_columns, max_column_width=self.args.max_column_width)
 
 
 def launch_new_instance():

docs/scripts/csvlook.rst

@@ -20,6 +20,18 @@ Renders a CSV to the command line in a readable, fixed-width format::
 
     optional arguments:
       -h, --help            show this help message and exit
+      --max-rows MAX_ROWS   The maximum number of rows to display before
+                            truncating the data.
+      --max-columns MAX_COLUMNS
+                            The maximum number of columns to display before
+                            truncating the data.
+      --max-column-width MAX_COLUMN_WIDTH
+                            Truncate all columns to at most this width. The
+                            remainder will be replaced with ellipsis.
+      -y SNIFF_LIMIT, --snifflimit SNIFF_LIMIT
+                            Limit CSV dialect sniffing to the specified number of
+                            bytes. Specify "0" to disable sniffing entirely.
+      --no-inference        Disable type inference when parsing the input.
 
 If a table is too wide to display properly try piping the output to ``less -S`` or truncating it using :doc:`csvcut`.
 

tests/test_utilities/test_csvlook.py

@@ -86,3 +86,30 @@ def test_sniff_limit_zero_limit(self):
             '|  1;2;3  |',
             '|---------|',
         ])
+
+    def test_max_rows(self):
+        self.assertLines(['--max-rows', '0', 'examples/dummy.csv'], [
+            '|----+---+----|',
+            '|  a | b | c  |',
+            '|----+---+----|',
+            '|  ... | ... | ...  |',
+            '|----+---+----|',
+        ])
+
+    def test_max_columns(self):
+        self.assertLines(['--max-columns', '1', 'examples/dummy.csv'], [
+            '|-------+------|',
+            '|     a | ...  |',
+            '|-------+------|',
+            '|  True | ...  |',
+            '|-------+------|',
+        ])
+
+    def test_max_column_width(self):
+        self.assertLines(['--max-column-width', '1', 'examples/dummy.csv'], [
+            '|--------+---+----|',
+            '|      a | b | c  |',
+            '|--------+---+----|',
+            '|  Tr... | 2 | 3  |',
+            '|--------+---+----|',
+        ])