csvlook: Add a --max-precision option, closes #941

CHANGELOG.rst

@@ -2,6 +2,7 @@ Unreleased
 ----------
 
 * :doc:`/scripts/csvformat` adds a :code:`--skip-header` (:code:`-E`) option to not output a header row.
+* :doc:`/scripts/csvlook` adds a :code:`--max-precision` option to set the maximum number of decimal places to display.
 * :doc:`/scripts/csvstat` supports the :code:`--no-inference` (:code:`-I`), :code:`--locale` (:code:`-L`), :code:`--blanks`, :code:`--date-format` and :code:`datetime-format` options.
 * :doc:`/scripts/csvstat` adds a :code:`--json` option to output results as JSON text.
 * :doc:`/scripts/csvstat` adds an :code:`--indent` option to indent the JSON text when :code:`--json` is set.

csvkit/utilities/csvlook.py

@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 
 import agate
+from agate import config
 
 from csvkit.cli import CSVKitUtility
 
@@ -18,6 +19,9 @@ def add_arguments(self):
         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(
+            '--max-precision', dest='max_precision', type=int,
+            help='The maximum number of decimal places to display. The remainder will be replaced with ellipsis.')
         self.argparser.add_argument(
             '-y', '--snifflimit', dest='sniff_limit', type=int, default=1024,
             help='Limit CSV dialect sniffing to the specified number of bytes. '
@@ -30,6 +34,9 @@ def main(self):
         if self.additional_input_expected():
             self.argparser.error('You must provide an input file or piped data.')
 
+        if self.args.max_precision is not None:
+            agate.set_option('decimal_truncation_chars', '')
+
         sniff_limit = self.args.sniff_limit if self.args.sniff_limit != -1 else None
         table = agate.Table.from_csv(
             self.input_file,
@@ -45,6 +52,7 @@ def main(self):
             max_rows=self.args.max_rows,
             max_columns=self.args.max_columns,
             max_column_width=self.args.max_column_width,
+            max_precision=self.args.max_precision,
         )
 
 

docs/scripts/csvlook.rst

@@ -34,11 +34,15 @@ Renders a CSV to the command line in a Markdown-compatible, fixed-width format:
      --max-column-width MAX_COLUMN_WIDTH
                            Truncate all columns to at most this width. The
                            remainder will be replaced with ellipsis.
+     --max-precision MAX_PRECISION
+                           The maximum number of decimal places to display. 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.
-     -I, --no-inference    Disable type inference when parsing the input.
-                           Disable reformatting of values.
+                           bytes. Specify "0" to disable sniffing entirely, or
+                           "-1" to sniff the entire file.
+     -I, --no-inference    Disable type inference when parsing the input. Disable
+                           reformatting of values.
 
 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

@@ -126,6 +126,13 @@ def test_max_column_width(self):
             '| Tr... | 2 | 3 |',
         ])
 
+    def test_max_precision(self):
+        self.assertLines(['--max-precision', '0', 'examples/date_like_number.csv'], [
+            '| a |',
+            '| - |',
+            '| 4 |',
+        ])
+
     def test_stdin(self):
         input_file = StringIO('a,b,c\n1,2,3\n4,5,6\n')