added random selection

CsvHandler.py

@@ -7,6 +7,7 @@ CsvHandler writes articles' information to csv file and reads it.
 
 import csv
 
+import numpy as np
 import pandas as pd
 
 class CsvHandler:
@@ -25,4 +26,28 @@ class CsvHandler:
 
     def write_csv(df, file_name):
         df.to_csv(file_name, sep='|')
-        print('# saved {} article(s) in {}'.format(len(df), file_name))
+        print('# saved {} article(s) in {}'.format(len(df), file_name))
+
+    def select_randoms(df, n):
+        '''selects n random samples from dataset.
+        params: df DataFrame to select items from,
+        n number of items to select randomly,
+        returns new DataFrame with only selected items
+        '''
+        # new empty DataFrame
+        df_samples = pd.DataFrame(columns=['rands','title','text','label'])
+        # initialize random => reproducible sequence
+        np.random.seed(5)
+        # pseudorandom float -1.0 <= x <= 1.0 for every sample
+        pd.Series()
+        # add new column 'Random'
+        df['Random'] = pd.Series(np.random.randn(len(df)), index=df.index)
+        # sort DataFrame by random numbers
+        df = df.sort_values('Random')
+        # return first n elements of randomly sorted dataset
+        return df.iloc[0:n]
+
+if __name__ == '__main__':
+    df = CsvHandler.read_csv('classification_labelled_corrected.csv')
+    df_new = CsvHandler.select_randoms(df, 10)
+    CsvHandler.write_csv(df_new, 'samples_10.csv')