1: Does the code run to completion without errors?
If there's an exception then the data may not get to the file because
I/O is normally buffered in memory and written out in larger chunks
as the buffer fills i.e. at a time later than your .writerow() call.
2: If you delete the CSV file before running your code, does it get
recreated? If not, maybe your filename is incorrect.
As a matter of practice you should write filenames using "raw" strings.
Instead of writing this:
with open("D:\PHD\obranking\\test_chi.csv", 'w') as csvfilew1:
it is better to write this:
with open(r'D:\PHD\obranking\test_chi.csvr', 'w') as csvfilew1:
In a raw string the backslash is not special and does not need to be
doubled. More importantly, the reason the backslash is special is that
in ordinary string syntax it is used to introduce various special
characters, such as "\n" to specify a newline character.
If you have an unfortunate filename such as:
D:\PHD\new_files
then you might easily produce a string with an embedded newline instead
of a file separator and an "n". Likewise for the various other escapes.
With a raw string like:
r'D:\PHD\new_files'
you do not run this risk.
Cheers,
Cameron Simpson <c...@cskk.id.au>
On 27Apr2020 09:14, Rahul Gupta <rahulgupta100...@gmail.com> wrote:
FOLLWOING IS MY CODE
import pandas as pd
import csv
from sklearn.preprocessing import LabelEncoder
from sklearn.feature_selection import chi2
with open("D:\PHD\obranking\\test_chi.csv", 'w') as csvfilew1:
fields = ['index', 'feature name', 'p_value']
csvwriter1 = csv.DictWriter(csvfilew1, fieldnames=fields)
csvwriter1.writeheader()
for i in range(1, 5502):
csv_data = dict().fromkeys(fields)
csv_data['index'] = i
cols =[]
cols.append(int(0))
cols.append(int(i))
df = pd.read_csv("D:\PHD\obranking\\demo.csv", usecols=cols)
df.apply(LabelEncoder().fit_transform)
X = df.drop(labels='label', axis=1)
Y = df['label']
chi_scores = chi2(X, Y)
if(chi_scores[1] < 0.05):
f_name = str(X.columns)
f_name = f_name[8:-19]
csv_data['feature name'] = f_name
p_val = str(chi_scores[1])
p_val = p_val[1:-1]
csv_data['p_value'] = p_val
print(csv_data)
csvwriter1.writerow(csv_data)
#print(csv_data)
#print(f_name + p_val)
#print(str(X.col + str(chi_scores[1]))
test_chi.csv is created but it remains empty after execution of the code.
although when i am printing csv_data it gets printed but not written in csv
using writerow(csv_data). Also there are no field names in the csv even
writeheader() seems to not work. I am confused what is wrong. Could someone
help????
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