Add csv output (#34)

Author: phensley

hdrh/histogram.py

@@ -597,12 +597,21 @@ def get_int_to_double_conversion_ratio(self):
     def output_percentile_distribution(self,
                                        out_file,
                                        output_value_unit_scaling_ratio,
-                                       ticks_per_half_distance=5):
-        out_file.write(b'%12s %14s %10s %14s\n\n' %
-                       (b'Value', b'Percentile', b'TotalCount', b'1/(1-Percentile)'))
+                                       ticks_per_half_distance=5,
+                                       use_csv=False):
+        if use_csv:
+            out_file.write(b'"Value","Percentile","TotalCount","1/(1-Percentile)"\n')
+        else:
+            out_file.write(b'%12s %14s %10s %14s\n\n' %
+                           (b'Value', b'Percentile', b'TotalCount', b'1/(1-Percentile)'))
+
+        if use_csv:
+            percentile_format = '%.{}f,%.12f,%d,%.2f\n'.format(self.significant_figures)
+            last_line_percentile_format = '%.{}f,%.12f,%d,Infinity\n'.format(self.significant_figures)
+        else:
+            percentile_format = '%12.{}f %2.12f %10d %14.2f\n'.format(self.significant_figures)
+            last_line_percentile_format = '%12.{}f %2.12f %10d\n'.format(self.significant_figures)
 
-        percentile_format = '%12.{}f %2.12f %10d %14.2f\n'.format(self.significant_figures)
-        last_line_percentile_format = '%12.{}f %2.12f %10d\n'.format(self.significant_figures)
         for iter_value in self.get_percentile_iterator(ticks_per_half_distance):
             value = iter_value.value_iterated_to / output_value_unit_scaling_ratio
             percentile = iter_value.percentile_level_iterated_to / 100
@@ -616,6 +625,9 @@ def output_percentile_distribution(self,
                                                                        percentile,
                                                                        total_count))
 
+        if use_csv:
+            return
+
         mean = self.get_mean_value() / output_value_unit_scaling_ratio
         stddev = self.get_stddev()
         out_file.write('#[Mean    = %12.{0}f, StdDeviation   = %12.{0}f]\n'.

test/test_hdrhistogram.py

@@ -24,6 +24,7 @@
 from builtins import range
 import cProfile
 import datetime
+import io
 import os
 import struct
 import zlib
@@ -50,6 +51,7 @@
 from hdrh.codec import HdrCookieException
 from hdrh.dump import dump
 
+
 def python_bitness():
     "cross-platform way of calculating bitness, returns either 32 or 64"
     return struct.calcsize("P") * 8
@@ -677,6 +679,16 @@ def test_output_percentile_distribution():
     histogram = load_histogram()
     histogram.output_percentile_distribution(open(os.devnull, 'wb'), 1000)
 
+@pytest.mark.log
+def test_output_percentile_distribution_csv():
+    buf = io.BytesIO()
+    histogram = load_histogram()
+    histogram.output_percentile_distribution(buf, 1000, use_csv=True)
+    lines = buf.getvalue().decode('utf-8').rstrip().split('\n')
+    assert lines[0] == '"Value","Percentile","TotalCount","1/(1-Percentile)"'
+    assert lines[1] == '1.000,0.000000000000,10000,1.00'
+    assert lines[-1] == '100007.935,1.000000000000,10001,Infinity'
+
 
 ARRAY_SIZE = 10
 

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py27, py36, py37, py38, pep8, lint
+envlist = py27, py36, py37, py38, py39, pep8, lint
 
 [testenv:pep8]
 commands = flake8 hdrh test