Answers for "write array to file python"

convert python list to text file

# define list of places
places = ['Berlin', 'Cape Town', 'Sydney', 'Moscow']

with open('listfile.txt', 'w') as filehandle:
    for listitem in places:
        filehandle.write('%s\n' % listitem)

how to save python list to file

import json
a = [1,2,3]
with open('test.txt', 'w') as f:
    f.write(json.dumps(a))

#Now read the file back into a Python list object
with open('test.txt', 'r') as f:
    a = json.loads(f.read())

how to write a numpy array to a file in python

numpy.savetxt(fname, X, fmt='%.18e', delimiter=' ', newline='\n', 
              header='', footer='', comments='# ', encoding=None)


x = y = z = np.arange(0.0,5.0,1.0)
np.savetxt('test.out', x, delimiter=',')   # X is an array
np.savetxt('test.out', (x,y,z))   # x,y,z equal sized 1D arrays
np.savetxt('test.out', x, fmt='%1.4e')   # use exponential notation

list to text file python

with open('your_file.txt', 'w') as f:
    for item in my_list:
        f.write("%s\n" % item)

array storing in file by python

# long arrays can be stored in csv files far more efficiently
import numpy as np
import csv

# uploading arrays in a csv file
arr1 = [i for i in range(500)]
arr2 = [i for i in range(1000)]
arr3 = [i for i in range(2000)]
# you can write('w') or append('a')
with open('record.csv', 'a') as record_append:
    np.savetxt(record_append, np.asarray([arr1]), delimiter=',')
    np.savetxt(record_append, np.asarray([arr2]), delimiter=',')
    np.savetxt(record_append, np.asarray([arr3]), delimiter=',')

# downloading them from the csv file
two_dim_arr = []  # each line of the file is an array element
with open('record.csv', 'r') as record_read:
    reader = csv.reader(record_read)
    for i, each_arr in enumerate(reader):
        two_dim_arr.append([eval(each) for each in each_arr])
        
# printing the arrays in lines
for each_line in two_dim_arr:
  print(each_line)