add outputting to csv

textattack/loggers/csv_logger.py

@@ -0,0 +1,20 @@
+import sys
+import os
+import pandas as pd
+import csv
+from textattack.loggers import Logger
+
+class CSVLogger(Logger):
+    def __init__(self, filename='results.csv', plain=False):
+        self.filename = filename
+        self.plain = plain
+        self.df = pd.DataFrame()
+
+    def log_attack_result(self, result, examples_completed):
+        color_method = None if self.plain else 'file'
+        s1, s2 = result.diff_color(color_method)
+        row = {'passage_1': s1, 'passage_2': s2} 
+        self.df = self.df.append(row, ignore_index=True)
+
+    def flush(self):
+        self.df.to_csv(self.filename, quoting=csv.QUOTE_NONNUMERIC)