i am searching everywhere for a method to write a list of floats into csv but must be in column format.
My code for writing csv as follow:
csvfile=open('Test.csv','w', newline='')
obj=csv.writer(csvfile)
obj.writerow(list_dis_B1_avg)
csvfile.close()
It turn out that the floats are written in rows.
I have a list of floats stored under "list_dis_B1_avg"
How can i just write it in column?
You dont need any csv module to do that:
with open("Test.csv", "w") as f: # use with to close the file in any case
f.write("\n".join(list_dis_B1_avg)) # newline between the elements
More about the with keyword: https://www.geeksforgeeks.org/with-statement-in-python/
More about str.join(): https://www.programiz.com/python-programming/methods/string/join
Related
I wrote the following code to split my data matrix into a csv file:
f = open('midi_data.csv', 'w', newline="")
writer = csv.writer(f, delimiter= ',',quotechar =',',quoting=csv.QUOTE_MINIMAL)
for item in data:
writer.writerow(item)
print(item)
f.close()
But the csv file ends up looking like this:
tuples not separated by columns but by commas in one column only
What am I doing wrong?
The data seems to be written correctly inside the tuples, because when running the code it outputs the following:
enter image description here
I have this script that reads a CSV and saves the second column to a list, I'm trying to get it to write the contents of the list to a new CSV. The problem is every entry should have its own row but the new file sets everything into the same row.
I've tried moving the second with open code to within the first with open and I've tried adding a for loop to the second with open but no matter what I try I don't get the right results.
Here is the code:
import csv
col_store=[]
with open('test-data.csv', 'r') as rf:
reader = csv.reader(rf)
for row in reader:
col_store.append(row[1])
with open('meow.csv', 'wt') as f:
csv_writer = csv.writer(f)
csv_writer.writerows([col_store])
In your case if you have a column of single letters/numbers then Y.R answer will work.
To have a code that works in all cases, use this.
with open('meow.csv', 'wt') as f:
csv_writer = csv.writer(f)
csv_writer.writerows(([_] for _ in col_store))
From here it is mentioned that writerows expect an an iterable of row objects. Every row object should be an iterable of strings or numbers for Writer objects
The problem is that you are using 'writerows' treating 'col_store' as a list with one item.
The simplest approach to fixing this is calling
csv_writer.writerows(col_store)
# instead of
csv_writer.writerows([col_store])
However, this will lead to a probably unwanted result - having blank lines between the lines.
To solve this, use:
with open('meow.csv', 'wt', newline='') as f:
csv_writer = csv.writer(f)
csv_writer.writerows(col_store)
For more about this, see CSV file written with Python has blank lines between each row
Note: writerows expects 'an iterable of row objects' and 'row objects must be an interable of strings or numbers'.
(https://docs.python.org/3/library/csv.html)
Therefore, in the generic case (trying to write integers for examlpe), you should use Sam's solution.
I have a list of dictionaries
d = [{'value':'foo_1', 'word_list':['blah1', 'blah2']}, ...., {'value': 'foo_n', 'word_list':['meh1', 'meh2']}]
I want to write this to a CSV file with all the 'value' keys in one column, and then each individual word from the "value"'s word_list as its own column. So I have the first row as
foo_1 blah_1 blah_2
and so on.
I don't know how many dictionaries I have, or how many words I have in "word_list".
How would I go about doing this in Python 3?
Thanks!
I figured out a solution, but it's kind of messy (wow, I can't write a bit of code without it being in the "proper format"...how annoying):
with open('filename', 'w') as f:
for key in d.keys():
f.write("%s,"%(key))
for word in d[key]:
f.write("%s,"%(word))
f.write("\n")
You can loop through the dictionaries one at a time, construct the list and then use the csv module to write the data as I have shown here
import csv
d = [{'value':'foo_1', 'word_list':['blah1', 'blah2']}, {'value': 'foo_n', 'word_list':['meh1', 'meh2']}]
with open('test_file.csv', 'w') as file:
writer = csv.writer(file)
for val_dict in d:
csv_row = [val_dict['value']] + val_dict['word_list']
writer.writerow(csv_row)
It should work for word lists of arbitrary length and as many dictionaries as you want.
It would probably be easiest to flatten each row into a normal list before writing it to the file. Something like this:
with open(filename, 'w') as file:
writer = csv.writer(file)
for row in data:
out_row = [row['value']]
for word in row['word_list']:
out_row.append(word)
csv.writerow(out_row)
# Shorter alternative to the two loops:
# csv.writerow((row['value'], *row['word_list']) for row in data)
I am trying something similar-
sample={"name":["age","number","email"]}
#dictionary stores the relevant data in above format
with open('selected.csv','w') as csvf:
[csvf.write('{0},{1}\n'.format(key,value)) for key,value in
sample.items()]
#writing data in a csv file with my formatting
"Aaron",[21,020303030,"Aaron#blahblah.com"]
#csv file sample entry
Everything works fine but CSV file shows List brackets, how can I remove them?
This isn't difficult if you use the standard library csv module:
import csv
sample={"name":["age","number","email"]}
with open('selected.csv', 'w+', newline='') as csvf:
writer = csv.writer(csvf)
for k, v in sample.items():
writer.writerow([k, *v]) # unpack v into a list with k
This would produce a file with one line:
name,age,number,email
I am trying read a CSV file into python 3 using unicodecsv library. Code follows :
with open('filename.csv', 'rb') as f:
reader = unicodecsv.DictReader(f)
Student_Data = list(reader)
But the order of the columns in the CSV file is not retained when I output any element from the Student_Data. The output contains any random order of the columns. Is there anything wrong with the code? How do I fix this?
As stated in csv.DictReader documentation, the DictReader object behaves like a dict - so it is not ordered.
You can obtain the list of the fieldnames with:
reader.fieldnames
But if you only want to obtain a list of the field values, in original order, you can just use a normal reader:
with open('filename.csv', 'rb') as f:
reader = unicodecsv.reader(f)
for row in reader:
Student_Data = row