Remove the last empty line from each text file - python

I have many text files, and each of them has a empty line at the end. My scripts did not seem to remove them. Can anyone help please?
# python 2.7
import os
import sys
import re
filedir = 'F:/WF/'
dir = os.listdir(filedir)
for filename in dir:
if 'ABC' in filename:
filepath = os.path.join(filedir,filename)
all_file = open(filepath,'r')
lines = all_file.readlines()
output = 'F:/WF/new/' + filename
# Read in each row and parse out components
for line in lines:
# Weed out blank lines
line = filter(lambda x: not x.isspace(), lines)
# Write to the new directory
f = open(output,'w')
f.writelines(line)
f.close()

You can use Python's rstrip() function to do this as follows:
filename = "test.txt"
with open(filename) as f_input:
data = f_input.read().rstrip('\n')
with open(filename, 'w') as f_output:
f_output.write(data)
This will remove all empty lines from the end of the file. It will not change the file if there are no empty lines.

you can remove last empty line by using:
with open(filepath, 'r') as f:
data = f.read()
with open(output, 'w') as w:
w.write(data[:-1])

You can try this without using the re module:
filedir = 'F:/WF/'
dir = os.listdir(filedir)
for filename in dir:
if 'ABC' in filename:
filepath = os.path.join(filedir,filename)
f = open(filepath).readlines()
new_file = open(filepath, 'w')
new_file.write('')
for i in f[:-1]:
new_file.write(i)
new_file.close()
For each filepath, the code opens the file, reads in its contents line by line, then writes over the file, and lastly writes the contents of f to the file, except for the last element in f, which is the empty line.

You can remove the last blank line by the following command. This worked for me:
file = open(file_path_src,'r')
lines = file.read()
with open(file_path_dst,'w') as f:
for indx, line in enumerate(lines):
f.write(line)
if indx != len(lines) - 1:
f.write('\n')

i think this should work fine
new_file.write(f[:-1])

Related

How to loop through directories and clean files?

I am trying to loop through directories. My goal is to open the directory ff for modifications in the files.
When I try open (ff, 'r') it does not work.
Further, the files in the directories d.txt has numbers and symbols x, 1, " in every line. I am seeking to remove these characters from each line.
import os
filenames= os.listdir (".")
for filename in filenames:
ff = os.path.join(r'C:\Users\V\Documents\f\e\e\data', filename, 'd.txt')
f = open(str(ff),'r') #this line does not open the file
a = ['x','1','"']
lst = []
for line in f:
for word in a:
if word in line:
line = line.replace(word,'')
lst.append(line)
f.close()
The Error that I am getting:
for line in f:
ValueError: I/O operation on closed file.
First of all, I think this part is wrong in your code:
for filename in filenames:
ff = os.path.join(r'C:\Users\V\Documents\f\e\e\data', filename, 'd.txt')
As this will assign the last filename to ff. So I have moved the following code under this for loop. Now it will run for all files.
I belive this code should work:
import os
filenames = os.listdir('.')
lst = []
a = ['x','1','"']
for filename in filenames:
ff = os.path.join(r'C:\Users\V\Documents\f\e\e\data', filename, 'd.txt')
with open(ff,'r') as file:
for line in file:
for word in a:
if word in line:
line = line.replace(word,'')
lst.append(line)
with open(ff,'w') as file:
for line in lst:
file.write(line)
Edit: if the open('ff','r') line doesn't work then maybe the path you are giving is wrong. What are the contents of filenames? And why are you adding d.txt at the end?? Please edit your post and add these details.
Move f.close() to outside of loop. You're closing the file everytime loop runs.
import os
filenames= os.listdir (".")
for filename in filenames:
ff = os.path.join(r'C:\Users\V\Documents\f\e\e\data', filename, 'd.txt')
f = open(str(ff),'r') #this line does not open the file
a = ['x','1','"']
lst = []
for line in f:
for word in a:
if word in line:
line = line.replace(word,'')
lst.append(line)
f.close()

How to edit specific line for all text files in a folder by python?

Here below is my code about how to edit text file.
Since python can't just edit a line and save it at the same time,
I save the previous text file's content into a list first then write it out.
For example,if there are two text files called sample1.txt and sample2.txt in the same folder.
Sample1.txt
A for apple.
Second line.
Third line.
Sample2.txt
First line.
An apple a day.
Third line.
Execute python
import glob
import os
#search all text files which are in the same folder with python script
path = os.path.dirname(os.path.abspath(__file__))
txtlist = glob.glob(path + '\*.txt')
for file in txtlist:
fp1 = open(file, 'r+')
strings = [] #create a list to store the content
for line in fp1:
if 'apple' in line:
strings.append('banana\n') #change the content and store into list
else:
strings.append(line) #store the contents did not be changed
fp2 = open (file, 'w+') # rewrite the original text files
for line in strings:
fp2.write(line)
fp1.close()
fp2.close()
Sample1.txt
banana
Second line.
Third line.
Sample2.txt
First line.
banana
Third line.
That's how I edit specific line for text file.
My question is : Is there any method can do the same thing?
Like using the other functions or using the other data type rather than list.
Thank you everyone.
Simplify it to this:
with open(fname) as f:
content = f.readlines()
content = ['banana' if line.find('apple') != -1 else line for line in content]
and then write value of content to file back.
Instead of putting all the lines in a list and writing it, you can read it into memory, replace, and write it using same file.
def replace_word(filename):
with open(filename, 'r') as file:
data = file.read()
data = data.replace('word1', 'word2')
with open(filename, 'w') as file:
file.write(data)
Then you can loop through all of your files and apply this function
The built-in fileinput module makes this quite simple:
import fileinput
import glob
with fileinput.input(files=glob.glob('*.txt'), inplace=True) as files:
for line in files:
if 'apple' in line:
print('banana')
else:
print(line, end='')
fileinput redirects print into the active file.
import glob
import os
def replace_line(file_path, replace_table: dict) -> None:
list_lines = []
need_rewrite = False
with open(file_path, 'r') as f:
for line in f:
flag_rewrite = False
for key, new_val in replace_table.items():
if key in line:
list_lines.append(new_val+'\n')
flag_rewrite = True
need_rewrite = True
break # only replace first find the words.
if not flag_rewrite:
list_lines.append(line)
if not need_rewrite:
return
with open(file_path, 'w') as f:
[f.write(line) for line in list_lines]
if __name__ == '__main__':
work_dir = os.path.dirname(os.path.abspath(__file__))
txt_list = glob.glob(work_dir + '/*.txt')
replace_dict = dict(apple='banana', orange='grape')
for txt_path in txt_list:
replace_line(txt_path, replace_dict)

Python; trying to add these files line by line with a tab inbetween

I'm reading in text files from the command line and I'm trying to produce output as follows...
Desired output given these command line arguments
Essentially, I want to read in files from the command line; take the first line from each file & print them on one line separated by a tab. Take the second line from each file & print them on the next line separated by a tab & so on.
This is the best code I've come up with (I'm a beginner and I've tried looking at other responses for far too long; glob & os hasn't been helping me understand how to do this; I'd just like to use basic loops and opening of files to do this):
import sys
l = []
list_files = sys.argv[:1]
for fname in list_files:
open(fname) as infile:
for line in infile:
line = line.strip()
if line == '':
l.append("''")
else:
l.append(line)
print(l) # List of all appended animals. Not in the right order
#(takes all names from one file, then all the names from the
#next instead of taking one line from every file on each iteration)
This is a minimally changed version that should work.
import sys
from itertools import zip_longest
files = []
list_files = sys.argv[:1]
for fname in list_files:
with open(fname) as infile: # Don't forget the `with`!
l = []
for line in infile:
line = line.strip()
if line == '':
l.append("''")
else:
l.append(line)
files.append(l) # list of lists
for lines in zip_longest(*files, fillvalue=''): # transpose list of lists
print(*lines, sep='\t') # separate with tabs.
The best way to open files in python is with with. More information can be found at https://www.pythonforbeginners.com/files/with-statement-in-python. Anyways:
import sys
if len(sys.argv) != 3:
sys.exit(1)
filename1 = sys.argv[1]
filename2 = sys.argv[2]
with open(filename1, 'r') as file1, open(filename2, 'r') as file2:
for line1, line2 in zip(file1, file2):
print(line1.strip(), line2.strip(), sep='\t')
This can be changed to allow for more than two files:
import sys
if len(sys.argv) != 3:
sys.exit(1)
filenames = sys.argv[1:]
all_lines = []
for filename in filenames:
with open(filename, 'r') as file:
all_lines.append([l.strip() for l in file.readlines()])
for line in zip(*all_lines):
print(*line, sep='\t')

automate change in python file and save with different filename

i have a python file named file_1.py
it has some code in which, i just have to change a word "file_1" to "file_2"
and also preserve indentation of other functions`
and save it as file_2.py
there are 3 occurances of the word file_1
i have to do this for 100 such times. `file_1.py, file_2.py.....file_100.py`
is there any way to automate this?
Run this script:
import fileinput
with fileinput.FileInput('file_1.py', inplace=True, backup='.bak') as file:
for line in file:
print(line.replace('file_1', 'file_2'), end='')
hope this help :)
create a script:
first: read file
with open("./file1.py") as f:
content = f.read()
second: replace filename
new_content = content.replace("file1","file2")
third: write new file(I would suggest you write a new file)
with open("./file2.py", "w") as f:
f.write(new_content)
if you have multiple files, use something like
filenames = ["file" + str(item) for item in range(1,100)]
for filename in filenames:
with open(filename + ".py") as f:
content = f.read()
new_filename = filename[:-1] + str(int(filename[-1]) + 1)
new_content = content.replace(filename,new_filename)
with open("./another_folder" + new_filename + ".py", "w") as f:
f.write(new_content)

Match the last word and delete the entire line

Input.txt File
12626232 : Bookmarks
1321121:
126262
Here 126262: can be anything text or digit, so basically will search for last word is : (colon) and delete the entire line
Output.txt File
12626232 : Bookmarks
My Code:
def function_example():
fn = 'input.txt'
f = open(fn)
output = []
for line in f:
if not ":" in line:
output.append(line)
f.close()
f = open(fn, 'w')
f.writelines(output)
f.close()
Problem: When I match with : it remove the entire line, but I just want to check if it is exist in the end of line and if it is end of the line then only remove the entire line.
Any suggestion will be appreciated. Thanks.
I saw as following but not sure how to use it in here
a = "abc here we go:"
print a[:-1]
I believe with this you should be able to achieve what you want.
with open(fname) as f:
lines = f.readlines()
for line in lines:
if not line.strip().endswith(':'):
print line
Here fname is the variable pointing to the file location.
You were almost there with your function. You were checking if : appears anywhere in the line, when you need to check if the line ends with it:
def function_example():
fn = 'input.txt'
f = open(fn)
output = []
for line in f:
if not line.strip().endswith(":"): # This is what you were missing
output.append(line)
f.close()
f = open(fn, 'w')
f.writelines(output)
f.close()
You could have also done if not line.strip()[:-1] == ':':, but endswith() is better suited for your use case.
Here is a compact way to do what you are doing above:
def function_example(infile, outfile, limiter=':'):
''' Filters all lines in :infile: that end in :limiter:
and writes the remaining lines to :outfile: '''
with open(infile) as in, open(outfile,'w') as out:
for line in in:
if not line.strip().endswith(limiter):
out.write(line)
The with statement creates a context and automatically closes files when the block ends.
To search if the last letter is : Do following
if line.strip().endswith(':'):
...Do Something...
You can use a regular expression
import re
#Something end with ':'
regex = re.compile('.(:+)')
new_lines = []
file_name = "path_to_file"
with open(file_name) as _file:
lines = _file.readlines()
new_lines = [line for line in lines if regex.search(line.strip())]
with open(file_name, "w") as _file:
_file.writelines(new_lines)

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