Writing to a file and maintain the syntax - python

Started with python after a long time:
Basically I am trying to read a line from a file:
MY_FILE ='test1.hgx'
Eventually I want to change this test1.hgx with:
test1_para1_para2_para3.hgx
Where para1,23 are the parameters I want to write.
I wrote a code below
add_name= '%s'%(filename)+'_'+'%s'%(para1)+'_'+'%s'%(para2)+'_'+'%s'%(para3)+'.hgx'
print "added_name:",add_name
with open(filename) as f: lines = f.read().splitlines()
with open(filename, 'w') as f:
for line in lines:
if line.startswith(' MY_FILE'):
f.write(line.rsplit(' ', 1)[0] + "\'%s'\n"%add_name)
else:
f.write(line + '\n')
f.close
The above code works as expected and writes out when I execute the python code once:
MY_FILE ='test1_01_02_03.hgx'
However when I run the python code once again for the second time it eats up the '=' and writes the following:
MY_FILE 'test1_01_02_03.hgx'
Can I add something to my existing code that would always preserve the writing of the 'test1_01_02_03.hgx'. I think there is problem with :
f.write(line.rsplit(' ', 1)[0] + "\'%s'\n"%add_name)
However I am not able to figure out the problem. Any ideas would be helpful. Thanks.


Change:
f.write(line.rsplit(' ', 1)[0] + "\'%s'\n"%add_name)
to
f.write(line.rsplit('=', 1)[0] + "=\'%s'\n"%add_name)
Incidentally, are you sure that in the original file, there wasn't a space after the =? If there is no space after the =, this code will always eat up the =. If there is a space, it won't eat it up until the second time the code is run.


You are splitting on ' ', which is before the =, but not adding another = back. There are many ways you can do this, but the easiest may be to simply add the = back in:
f.write(line.rsplit(' ', 1)[0] + "='%s'\n" % add_name)
Another, cleaner, way to do it would be to use replace:
f.write(line.replace(filename, new_name))
As an aside, you can write the first line much better as:
add_name = '%s_%s_%s_%s.hgx' % (filename, para1, para2, para3)


Try using the fileinput module. Also, use format() to write into strings.
# Using the fileinput module we can open a file and write to it using stdout.
import fileinput
# using stdout we avoid the formatting of print, and avoid extra newlines.
import sys
filename = 'testfile'
params = ['foo', 'bar', 'baz']
# Build the new replacement line.
newline = '{0}_{1}_(2)_{3}.hgx'.format(filename, params[0], params[1], params[2])
for line in fileinput.input(filename, inplace=1):
if line.startswith('MY_FILE'):
sys.stdout.write('MYFILE = {0}\n'.format(newline))
else:
sys.stdout.write(line)
This should replace any line starting with MYFILE with the lineMYFILE = 'testfile_foo_bar_baz.hgz

Related

Send keylogger log files to e-mail [duplicate]

I have a text file that looks like:
ABC
DEF
How can I read the file into a single-line string without newlines, in this case creating a string 'ABCDEF'?
For reading the file into a list of lines, but removing the trailing newline character from each line, see How to read a file without newlines?.

You could use:
with open('data.txt', 'r') as file:
data = file.read().replace('\n', '')
Or if the file content is guaranteed to be one-line
with open('data.txt', 'r') as file:
data = file.read().rstrip()

In Python 3.5 or later, using pathlib you can copy text file contents into a variable and close the file in one line:
from pathlib import Path
txt = Path('data.txt').read_text()
and then you can use str.replace to remove the newlines:
txt = txt.replace('\n', '')

You can read from a file in one line:
str = open('very_Important.txt', 'r').read()
Please note that this does not close the file explicitly.
CPython will close the file when it exits as part of the garbage collection.
But other python implementations won't. To write portable code, it is better to use with or close the file explicitly. Short is not always better. See https://stackoverflow.com/a/7396043/362951

To join all lines into a string and remove new lines, I normally use :
with open('t.txt') as f:
s = " ".join([l.rstrip("\n") for l in f])

with open("data.txt") as myfile:
data="".join(line.rstrip() for line in myfile)
join() will join a list of strings, and rstrip() with no arguments will trim whitespace, including newlines, from the end of strings.

This can be done using the read() method :
text_as_string = open('Your_Text_File.txt', 'r').read()
Or as the default mode itself is 'r' (read) so simply use,
text_as_string = open('Your_Text_File.txt').read()

I'm surprised nobody mentioned splitlines() yet.
with open ("data.txt", "r") as myfile:
data = myfile.read().splitlines()
Variable data is now a list that looks like this when printed:
['LLKKKKKKKKMMMMMMMMNNNNNNNNNNNNN', 'GGGGGGGGGHHHHHHHHHHHHHHHHHHHHEEEEEEEE']
Note there are no newlines (\n).
At that point, it sounds like you want to print back the lines to console, which you can achieve with a for loop:
for line in data:
print(line)

It's hard to tell exactly what you're after, but something like this should get you started:
with open ("data.txt", "r") as myfile:
data = ' '.join([line.replace('\n', '') for line in myfile.readlines()])

I have fiddled around with this for a while and have prefer to use use read in combination with rstrip. Without rstrip("\n"), Python adds a newline to the end of the string, which in most cases is not very useful.
with open("myfile.txt") as f:
file_content = f.read().rstrip("\n")
print(file_content)

Here are four codes for you to choose one:
with open("my_text_file.txt", "r") as file:
data = file.read().replace("\n", "")
or
with open("my_text_file.txt", "r") as file:
data = "".join(file.read().split("\n"))
or
with open("my_text_file.txt", "r") as file:
data = "".join(file.read().splitlines())
or
with open("my_text_file.txt", "r") as file:
data = "".join([line for line in file])

you can compress this into one into two lines of code!!!
content = open('filepath','r').read().replace('\n',' ')
print(content)
if your file reads:
hello how are you?
who are you?
blank blank
python output
hello how are you? who are you? blank blank

You can also strip each line and concatenate into a final string.
myfile = open("data.txt","r")
data = ""
lines = myfile.readlines()
for line in lines:
data = data + line.strip();
This would also work out just fine.

This is a one line, copy-pasteable solution that also closes the file object:
_ = open('data.txt', 'r'); data = _.read(); _.close()

f = open('data.txt','r')
string = ""
while 1:
line = f.readline()
if not line:break
string += line
f.close()
print(string)

python3: Google "list comprehension" if the square bracket syntax is new to you.
with open('data.txt') as f:
lines = [ line.strip('\n') for line in list(f) ]

Oneliner:
List: "".join([line.rstrip('\n') for line in open('file.txt')])
Generator: "".join((line.rstrip('\n') for line in open('file.txt')))
List is faster than generator but heavier on memory. Generators are slower than lists and is lighter for memory like iterating over lines. In case of "".join(), I think both should work well. .join() function should be removed to get list or generator respectively.
Note: close() / closing of file descriptor probably not needed

Have you tried this?
x = "yourfilename.txt"
y = open(x, 'r').read()
print(y)

To remove line breaks using Python you can use replace function of a string.
This example removes all 3 types of line breaks:
my_string = open('lala.json').read()
print(my_string)
my_string = my_string.replace("\r","").replace("\n","")
print(my_string)
Example file is:
{
"lala": "lulu",
"foo": "bar"
}
You can try it using this replay scenario:
https://repl.it/repls/AnnualJointHardware

I don't feel that anyone addressed the [ ] part of your question. When you read each line into your variable, because there were multiple lines before you replaced the \n with '' you ended up creating a list. If you have a variable of x and print it out just by
x
or print(x)
or str(x)
You will see the entire list with the brackets. If you call each element of the (array of sorts)
x[0]
then it omits the brackets. If you use the str() function you will see just the data and not the '' either.
str(x[0])

Maybe you could try this? I use this in my programs.
Data= open ('data.txt', 'r')
data = Data.readlines()
for i in range(len(data)):
data[i] = data[i].strip()+ ' '
data = ''.join(data).strip()

Regular expression works too:
import re
with open("depression.txt") as f:
l = re.split(' ', re.sub('\n',' ', f.read()))[:-1]
print (l)
['I', 'feel', 'empty', 'and', 'dead', 'inside']

with open('data.txt', 'r') as file:
data = [line.strip('\n') for line in file.readlines()]
data = ''.join(data)

from pathlib import Path
line_lst = Path("to/the/file.txt").read_text().splitlines()
Is the best way to get all the lines of a file, the '\n' are already stripped by the splitlines() (which smartly recognize win/mac/unix lines types).
But if nonetheless you want to strip each lines:
line_lst = [line.strip() for line in txt = Path("to/the/file.txt").read_text().splitlines()]
strip() was just a useful exemple, but you can process your line as you please.
At the end, you just want concatenated text ?
txt = ''.join(Path("to/the/file.txt").read_text().splitlines())

This works:
Change your file to:
LLKKKKKKKKMMMMMMMMNNNNNNNNNNNNN GGGGGGGGGHHHHHHHHHHHHHHHHHHHHEEEEEEEE
Then:
file = open("file.txt")
line = file.read()
words = line.split()
This creates a list named words that equals:
['LLKKKKKKKKMMMMMMMMNNNNNNNNNNNNN', 'GGGGGGGGGHHHHHHHHHHHHHHHHHHHHEEEEEEEE']
That got rid of the "\n". To answer the part about the brackets getting in your way, just do this:
for word in words: # Assuming words is the list above
print word # Prints each word in file on a different line
Or:
print words[0] + ",", words[1] # Note that the "+" symbol indicates no spaces
#The comma not in parentheses indicates a space
This returns:
LLKKKKKKKKMMMMMMMMNNNNNNNNNNNNN, GGGGGGGGGHHHHHHHHHHHHHHHHHHHHEEEEEEEE

with open(player_name, 'r') as myfile:
data=myfile.readline()
list=data.split(" ")
word=list[0]
This code will help you to read the first line and then using the list and split option you can convert the first line word separated by space to be stored in a list.
Than you can easily access any word, or even store it in a string.
You can also do the same thing with using a for loop.

file = open("myfile.txt", "r")
lines = file.readlines()
str = '' #string declaration
for i in range(len(lines)):
str += lines[i].rstrip('\n') + ' '
print str

Try the following:
with open('data.txt', 'r') as myfile:
data = myfile.read()
sentences = data.split('\\n')
for sentence in sentences:
print(sentence)
Caution: It does not remove the \n. It is just for viewing the text as if there were no \n

reading in file python says its a string [duplicate]

I have a text file that looks like:
ABC
DEF
How can I read the file into a single-line string without newlines, in this case creating a string 'ABCDEF'?
For reading the file into a list of lines, but removing the trailing newline character from each line, see How to read a file without newlines?.

You could use:
with open('data.txt', 'r') as file:
data = file.read().replace('\n', '')
Or if the file content is guaranteed to be one-line
with open('data.txt', 'r') as file:
data = file.read().rstrip()

In Python 3.5 or later, using pathlib you can copy text file contents into a variable and close the file in one line:
from pathlib import Path
txt = Path('data.txt').read_text()
and then you can use str.replace to remove the newlines:
txt = txt.replace('\n', '')

You can read from a file in one line:
str = open('very_Important.txt', 'r').read()
Please note that this does not close the file explicitly.
CPython will close the file when it exits as part of the garbage collection.
But other python implementations won't. To write portable code, it is better to use with or close the file explicitly. Short is not always better. See https://stackoverflow.com/a/7396043/362951

To join all lines into a string and remove new lines, I normally use :
with open('t.txt') as f:
s = " ".join([l.rstrip("\n") for l in f])

with open("data.txt") as myfile:
data="".join(line.rstrip() for line in myfile)
join() will join a list of strings, and rstrip() with no arguments will trim whitespace, including newlines, from the end of strings.

This can be done using the read() method :
text_as_string = open('Your_Text_File.txt', 'r').read()
Or as the default mode itself is 'r' (read) so simply use,
text_as_string = open('Your_Text_File.txt').read()

I'm surprised nobody mentioned splitlines() yet.
with open ("data.txt", "r") as myfile:
data = myfile.read().splitlines()
Variable data is now a list that looks like this when printed:
['LLKKKKKKKKMMMMMMMMNNNNNNNNNNNNN', 'GGGGGGGGGHHHHHHHHHHHHHHHHHHHHEEEEEEEE']
Note there are no newlines (\n).
At that point, it sounds like you want to print back the lines to console, which you can achieve with a for loop:
for line in data:
print(line)

It's hard to tell exactly what you're after, but something like this should get you started:
with open ("data.txt", "r") as myfile:
data = ' '.join([line.replace('\n', '') for line in myfile.readlines()])

I have fiddled around with this for a while and have prefer to use use read in combination with rstrip. Without rstrip("\n"), Python adds a newline to the end of the string, which in most cases is not very useful.
with open("myfile.txt") as f:
file_content = f.read().rstrip("\n")
print(file_content)

Here are four codes for you to choose one:
with open("my_text_file.txt", "r") as file:
data = file.read().replace("\n", "")
or
with open("my_text_file.txt", "r") as file:
data = "".join(file.read().split("\n"))
or
with open("my_text_file.txt", "r") as file:
data = "".join(file.read().splitlines())
or
with open("my_text_file.txt", "r") as file:
data = "".join([line for line in file])

you can compress this into one into two lines of code!!!
content = open('filepath','r').read().replace('\n',' ')
print(content)
if your file reads:
hello how are you?
who are you?
blank blank
python output
hello how are you? who are you? blank blank

You can also strip each line and concatenate into a final string.
myfile = open("data.txt","r")
data = ""
lines = myfile.readlines()
for line in lines:
data = data + line.strip();
This would also work out just fine.

This is a one line, copy-pasteable solution that also closes the file object:
_ = open('data.txt', 'r'); data = _.read(); _.close()

f = open('data.txt','r')
string = ""
while 1:
line = f.readline()
if not line:break
string += line
f.close()
print(string)

python3: Google "list comprehension" if the square bracket syntax is new to you.
with open('data.txt') as f:
lines = [ line.strip('\n') for line in list(f) ]

Oneliner:
List: "".join([line.rstrip('\n') for line in open('file.txt')])
Generator: "".join((line.rstrip('\n') for line in open('file.txt')))
List is faster than generator but heavier on memory. Generators are slower than lists and is lighter for memory like iterating over lines. In case of "".join(), I think both should work well. .join() function should be removed to get list or generator respectively.
Note: close() / closing of file descriptor probably not needed

Have you tried this?
x = "yourfilename.txt"
y = open(x, 'r').read()
print(y)

To remove line breaks using Python you can use replace function of a string.
This example removes all 3 types of line breaks:
my_string = open('lala.json').read()
print(my_string)
my_string = my_string.replace("\r","").replace("\n","")
print(my_string)
Example file is:
{
"lala": "lulu",
"foo": "bar"
}
You can try it using this replay scenario:
https://repl.it/repls/AnnualJointHardware

I don't feel that anyone addressed the [ ] part of your question. When you read each line into your variable, because there were multiple lines before you replaced the \n with '' you ended up creating a list. If you have a variable of x and print it out just by
x
or print(x)
or str(x)
You will see the entire list with the brackets. If you call each element of the (array of sorts)
x[0]
then it omits the brackets. If you use the str() function you will see just the data and not the '' either.
str(x[0])

Maybe you could try this? I use this in my programs.
Data= open ('data.txt', 'r')
data = Data.readlines()
for i in range(len(data)):
data[i] = data[i].strip()+ ' '
data = ''.join(data).strip()

Regular expression works too:
import re
with open("depression.txt") as f:
l = re.split(' ', re.sub('\n',' ', f.read()))[:-1]
print (l)
['I', 'feel', 'empty', 'and', 'dead', 'inside']

with open('data.txt', 'r') as file:
data = [line.strip('\n') for line in file.readlines()]
data = ''.join(data)

from pathlib import Path
line_lst = Path("to/the/file.txt").read_text().splitlines()
Is the best way to get all the lines of a file, the '\n' are already stripped by the splitlines() (which smartly recognize win/mac/unix lines types).
But if nonetheless you want to strip each lines:
line_lst = [line.strip() for line in txt = Path("to/the/file.txt").read_text().splitlines()]
strip() was just a useful exemple, but you can process your line as you please.
At the end, you just want concatenated text ?
txt = ''.join(Path("to/the/file.txt").read_text().splitlines())

This works:
Change your file to:
LLKKKKKKKKMMMMMMMMNNNNNNNNNNNNN GGGGGGGGGHHHHHHHHHHHHHHHHHHHHEEEEEEEE
Then:
file = open("file.txt")
line = file.read()
words = line.split()
This creates a list named words that equals:
['LLKKKKKKKKMMMMMMMMNNNNNNNNNNNNN', 'GGGGGGGGGHHHHHHHHHHHHHHHHHHHHEEEEEEEE']
That got rid of the "\n". To answer the part about the brackets getting in your way, just do this:
for word in words: # Assuming words is the list above
print word # Prints each word in file on a different line
Or:
print words[0] + ",", words[1] # Note that the "+" symbol indicates no spaces
#The comma not in parentheses indicates a space
This returns:
LLKKKKKKKKMMMMMMMMNNNNNNNNNNNNN, GGGGGGGGGHHHHHHHHHHHHHHHHHHHHEEEEEEEE

with open(player_name, 'r') as myfile:
data=myfile.readline()
list=data.split(" ")
word=list[0]
This code will help you to read the first line and then using the list and split option you can convert the first line word separated by space to be stored in a list.
Than you can easily access any word, or even store it in a string.
You can also do the same thing with using a for loop.

file = open("myfile.txt", "r")
lines = file.readlines()
str = '' #string declaration
for i in range(len(lines)):
str += lines[i].rstrip('\n') + ' '
print str

Try the following:
with open('data.txt', 'r') as myfile:
data = myfile.read()
sentences = data.split('\\n')
for sentence in sentences:
print(sentence)
Caution: It does not remove the \n. It is just for viewing the text as if there were no \n

How to concatenate a string in python?

I try to read in a file and output in a single line.
File:
how
are
you
code:
infile = open('input', 'r')
for line in infile:
line = line.rstrip('\n')
print (line)
rstrip already strip off '\n',
however the output still spread into 3 lines.
how
are
you
How to make the print out into single line?

Just pass empty string to end parameter in print function after strippping off the newline character.
print (line, end = "")
print by default print the content in a new line for each iteration but by passing empty string to the end parameter, this default behaviour won't work. If you failed to remove the newline character, it would print the content along with the newline character.

Because the print() function is being called independently each time the loop runs. And every time the print runs, the output is started to be printed on a new line.

The title asks for concatenation but the details just ask for output. The print answers deals with the latter but if you want to concatenate, then you would use join or +
>>> with open('input', 'r') as infile:
... output = ""
... for line in infile:
... output += line.rstrip('\n')
... print(output)
howareyou
However, given you likely want a space between the strings then I would suggest you look into join, which can simply be used in conjunction with a comprehension:
>>> with open('input', 'r') as infile:
... print(" ".join(line.rstrip(`\n`) for line in infile))
how are you

If you use python 2.7, the following syntax should work:
print line,

to make 2&3 compatible, you can:
from __future__ import print_function
print('hello, world', end='')
so your code could be:
from __future__ import print_function
infile = open('input', 'r')
for line in infile:
line = line.rstrip('\n')
print(line, end='')
or this one:
with open('input') as f:
lines = [line.strip() for line in f.readlines()]
print(' '.join(lines))

Splitting lines in python based on some character

Input:
!,A,56281,12/12/19,19:34:12,000.0,0,37N22.714,121W55.576,+0013!,A,56281,12/1
2/19,19:34:13,000.0,0,37N22.714,121W55.576,+0013!,A,56281,12/12/19,19:34:14,000.
0,0,37N22.714,121W55.576,+0013!,A,56281,12/12/19,19:34:15,000.0,0,37N22.714,121W
55.576,+0013!,A,56281,12/12/19,19:34:16,000.0,0,37N22.714,121W55.576,+0013!,A,56
281,12/12/19,19:34:17,000.0,0,37N22.714,121W55.576,+0013!,A,56281,12/12/19,19:34
:18,000.0,0,37N22.714,121W55.576,+0013!,A,56281,12/12/19,19:34:19,000.0,0,37N22.
Output:
!,A,56281,12/12/19,19:34:12,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:13,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:14,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:15,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:16,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:17,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:18,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:19,000.0,0,37N22.
'!' is the starting character and +0013 should be the ending of each line (if present).
Problem which I am getting:
Output is like :
!,A,56281,12/12/19,19:34:12,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/1
2/19,19:34:13,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:14,000.
0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:15,000.0,0,37N22.714,121W
Any help would be highly appreciated...!!!
My code:
file_open= open('sample.txt','r')
file_read= file_open.read()
file_open2= open('output.txt','w+')
counter =0
for i in file_read:
if '!' in i:
if counter == 1:
file_open2.write('\n')
counter= counter -1
counter= counter +1
file_open2.write(i)

You can try something like this:
with open("abc.txt") as f:
data=f.read().replace("\r\n","") #replace the newlines with ""
#the newline can be "\n" in your system instead of "\r\n"
ans=filter(None,data.split("!")) #split the data at '!', then filter out empty lines
for x in ans:
print "!"+x #or write to some other file
.....:
!,A,56281,12/12/19,19:34:12,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:13,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:14,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:15,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:16,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:17,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:18,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:19,000.0,0,37N22.

Could you just use str.split?
lines = file_read.split('!')
Now lines is a list which holds the split data. This is almost the lines you want to write -- The only difference is that they don't have trailing newlines and they don't have '!' at the start. We can put those in easily with string formatting -- e.g. '!{0}\n'.format(line). Then we can put that whole thing in a generator expression which we'll pass to file.writelines to put the data in a new file:
file_open2.writelines('!{0}\n'.format(line) for line in lines)
You might need:
file_open2.writelines('!{0}\n'.format(line.replace('\n','')) for line in lines)
if you find that you're getting more newlines than you wanted in the output.
A few other points, when opening files, it's nice to use a context manager -- This makes sure that the file is closed properly:
with open('inputfile') as fin:
lines = fin.read()
with open('outputfile','w') as fout:
fout.writelines('!{0}\n'.format(line.replace('\n','')) for line in lines)

Another option, using replace instead of split, since you know the starting and ending characters of each line:
In [14]: data = """!,A,56281,12/12/19,19:34:12,000.0,0,37N22.714,121W55.576,+0013!,A,56281,12/1
2/19,19:34:13,000.0,0,37N22.714,121W55.576,+0013!,A,56281,12/12/19,19:34:14,000.
0,0,37N22.714,121W55.576,+0013!,A,56281,12/12/19,19:34:15,000.0,0,37N22.714,121W
55.576,+0013!,A,56281,12/12/19,19:34:16,000.0,0,37N22.714,121W55.576,+0013!,A,56
281,12/12/19,19:34:17,000.0,0,37N22.714,121W55.576,+0013!,A,56281,12/12/19,19:34
:18,000.0,0,37N22.714,121W55.576,+0013!,A,56281,12/12/19,19:34:19,000.0,0,37N22.""".replace('\n', '')
In [15]: print data.replace('+0013!', "+0013\n!")
!,A,56281,12/12/19,19:34:12,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:13,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:14,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:15,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:16,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:17,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:18,000.0,0,37N22.714,121W55.576,+0013
!,A,56281,12/12/19,19:34:19,000.0,0,37N22.

Just for some variance, here is a regular expression answer:
import re
outputFile = open('output.txt', 'w+')
with open('sample.txt', 'r') as f:
for line in re.findall("!.+?(?=!|$)", f.read(), re.DOTALL):
outputFile.write(line.replace("\n", "") + '\n')
outputFile.close()
It will open the output file, get the contents of the input file, and loop through all the matches using the regular expression !.+?(?=!|$) with the re.DOTALL flag. The regular expression explanation & what it matches can be found here: http://regex101.com/r/aK6aV4
After we have a match, we strip out the new lines from the match, and write it to the file.

Let's try to add a \n before every "!"; then let python splitlines :-) :
file_read.replace("!", "!\n").splitlines()

I will actually implement as a generator so that you can work on the data stream rather than the entire content of the file. This will be quite memory friendly if working with huge files
>>> def split_on_stream(it,sep="!"):
prev = ""
for line in it:
line = (prev + line.strip()).split(sep)
for parts in line[:-1]:
yield parts
prev = line[-1]
yield prev
>>> with open("test.txt") as fin:
for parts in split_on_stream(fin):
print parts
,A,56281,12/12/19,19:34:12,000.0,0,37N22.714,121W55.576,+0013
,A,56281,12/12/19,19:34:13,000.0,0,37N22.714,121W55.576,+0013
,A,56281,12/12/19,19:34:14,000.0,0,37N22.714,121W55.576,+0013
,A,56281,12/12/19,19:34:15,000.0,0,37N22.714,121W55.576,+0013
,A,56281,12/12/19,19:34:16,000.0,0,37N22.714,121W55.576,+0013
,A,56281,12/12/19,19:34:17,000.0,0,37N22.714,121W55.576,+0013
,A,56281,12/12/19,19:34:18,000.0,0,37N22.714,121W55.576,+0013
,A,56281,12/12/19,19:34:19,000.0,0,37N22.

Python- How to Remove Columns from a File

I'd like to remove the first column from a file. The file contains 3 columns separated by space and the columns has the following titles:
X', 'Displacement' and 'Force' (Please see the image).
I have came up with the following code, but to my disappointment it doesn't work!
f = open("datafile.txt", 'w')
for line in f:
line = line.split()
del x[0]
f.close()
Any help is much appreciated !
Esan

First of all, you're attempting to read from a file (by iterating through the file contents) that is open for writing. This will give you an IOError.
Second, there is no variable named x in existence (you have not declared/set one in the script). This will generate a NameError.
Thirdly and finally, once you have finished (correctly) reading and editing the columns in your file, you will need to write the data back into the file.
To avoid loading a (potentially large) file into memory all at once, it is probably a good idea to read from one file (line by line) and write to a new file simultaneously.
Something like this might work:
f = open("datafile.txt", "r")
g = open("datafile_fixed.txt", "w")
for line in f:
if line.strip():
g.write("\t".join(line.split()[1:]) + "\n")
f.close()
g.close()

Some reading about python i/o might be helpful, but something like the following should get you on your feet:
with open("datafile.txt", "r") as fin:
with open("outputfile.txt", "w") as fout:
for line in fin:
line = line.split(' ')
if len(line) == 3:
del line[0]
fout.write(line[0] + ' ' + line[1])
else:
fout.write('\n')
EDIT: fixed to work with blank lines

print ''.join([' '.join(l.split()[1:]) for l in file('datafile.txt')])
or, if you want to preserve spaces and you know that the second column always starts at the, say, 10th character:
print ''.join([l[11:] for l in file('datafile.txt')])

Categories