Geek asks and answers

Is there a way to read the .txt file and save each line in memory?

I am making a small program that will read and display text from a document. I have a test file that looks like this:

12,12,12
12,31,12
1,5,3
...

etc. Now, I would like Python to read every line and store it in memory, so when you choose to display data, it displays it in the shell as such:

1. 12,12,12
2. 12,31,12
...

etc. How can i do this?

+5
source share
6 answers

I know I already answered :) To summarize the above:

# It is a good idea to store the filename into a variable.
# The variable can later become a function argument when the
# code is converted to a function body.
filename = 'data.txt'

# Using the newer with construct to close the file automatically.
with open(filename) as f:
    data = f.readlines()

# Or using the older approach and closing the filea explicitly.
# Here the data is re-read again, do not use both ;)
f = open(filename)
data = f.readlines()
f.close()


# The data is of the list type.  The Python list type is actually
# a dynamic array. The lines contain also the \n; hence the .rstrip()
for n, line in enumerate(data, 1):
    print '{:2}.'.format(n), line.rstrip()

print '-----------------'

# You can later iterate through the list for other purpose, for
# example to read them via the csv.reader.
import csv

reader = csv.reader(data)
for row in reader:
    print row

It prints on my console:

 1. 12,12,12
 2. 12,31,12
 3. 1,5,3
-----------------
['12', '12', '12']
['12', '31', '12']
['1', '5', '3']
+13
source

Try to save it in an array

f = open( "file.txt", "r" )
a = []
for line in f:
    a.append(line)
+4
source

csv. , , (csv)... , -, .

:

import csv
reader = csv.reader( open( 'file.txt', 'rb'), delimiter=',' )
#Iterate over each row
for idx,row in enumerate(reader):
    print "%s: %s"%(idx+1,row)
+1

Thanks for the excellent @PePr solution. Alternatively, you can try to print the .txt file with the built-in method String.join(data). For instance:

with open(filename) as f:
    data = f.readlines()
print(''.join(data))
+1
source 
with open('test.txt') as o:
    for i,t in enumerate(o.readlines(), 1):
        print ("%s. %s"% (i, t))
0
source 
#!/usr/local/bin/python

t=1

with open('sample.txt') as inf:
    for line in inf:
        num = line.strip() # contains current line
        if num:
            fn = '%d.txt' %t # gives the name to files t= 1.txt,2.txt,3.txt .....
            print('%d.txt Files splitted' %t)
            #fn = '%s.txt' %num
            with open(fn, 'w') as outf:
                outf.write('%s\n' %num) # writes current line in opened fn file
                t=t+1
0
source

More articles:


All Articles