I have to parse some data, I've successfully made a script that finds the start and end of the test, and will print out the data in between those.
Python, the line here is from the csv library
else:
print(line)
# csv_file = open(title+'.txt', "w")
# writer = csv.writer(csv_file)
# csv.writer(csv_file).writerow(line)
the csv writes extremely funky data instead of the line as a row. Printing out the line looks exactly as it does in the txt file.
Printing out the line looks exactly as it does in the txt file.
print function does accept optional file argument so if you want to write file exactly like it would look at stdout you might do
...
with open("file.txt","w") as f:
print(line, file=f)
Related
I have a .sql file, when i am trying to read data from .sql file using python open() function it's reading the file only in readlines() method. And removing the \n and spaces, I am trying to convert into .txt file which is not happening. I don't have connection params.
sql_file = open('SQL_SCript.sql', 'r')
lines = sql_file.readlines()
for line in lines:
line.strip()
with open('new_sql_script.txt', 'w') as new_sql_file:
new_sql_file.write(str(lines))
If all you need to do is change the extension, why no just copy to a new file with the right name. An SQL file is still a text file.
import shutil
shutil.copyfile('SQL_SCript.sql', 'new_sql_script.txt')
If you're determined to do it by reading and writing, it looks like what you're currently doing is overwriting the last line on every iteration.
You want something like this:
with open('SQL_SCript.sql') as in_file:
with open('new_sql_script', 'w') as out_file:
for line in in_file:
out_file.write(line)
I wrote the following python code snippet to append a lower p character to each line of a txt file:
f = open('helloworld.txt','r')
for line in f:
line+='p'
print(f.read())
f.close()
However, when I execute this python program, it returns nothing but an empty blank:
zhiwei#zhiwei-Lenovo-Rescuer-15ISK:~/Documents/1001/ass5$ python3 helloworld.py
Can anyone tell me what's wrong with my codes?
Currently, you are only reading each line and not writing to the file. reopen the file in write mode and write your full string to it, like so:
newf=""
with open('helloworld.txt','r') as f:
for line in f:
newf+=line.strip()+"p\n"
f.close()
with open('helloworld.txt','w') as f:
f.write(newf)
f.close()
well, type help(f) in shell, you can get "Character and line based layer over a BufferedIOBase object, buffer."
it's meaning：if you reading first buffer,you can get content, but again. it's empty。
so like this:
with open(oldfile, 'r') as f1, open(newfile, 'w') as f2:
newline = ''
for line in f1:
newline+=line.strip()+"p\n"
f2.write(newline)
open(filePath, openMode) takes two arguments, the first one is the path to your file, the second one is the mode it will be opened it. When you use 'r' as second argument, you are actually telling Python to open it as an only reading file.
If you want to write on it, you need to open it in writing mode, using 'w' as second argument. You can find more about how to read/write files in Python in its official documentation.
If you want to read and write at the same time, you have to open the file in both reading and writing modes. You can do this simply by using 'r+' mode.
It seems that your for loop has already read the file to the end, so f.read() return empty string.
If you just need to print the lines in the file, you could move the print into for loop just like print(line). And it is better to move the f.read() before for loop:
f = open("filename", "r")
lines = f.readlines()
for line in lines:
line += "p"
print(line)
f.close()
If you need to modify the file, you need to create another file obj and open it in mode of "w", and use f.write(line) to write the modified lines into the new file.
Besides, it is more better to use with clause in python instead of open(), it is more pythonic.
with open("filename", "r") as f:
lines = f.readlines()
for line in lines:
line += "p"
print(line)
When using with clause, you have no need to close file, this is more simple.
I'm doing a program where I export an excel file to .txt and I have to import this .txt file into my program. The main goal is to extract the same part from each line but the problem is that in the .txt file the lines of the excel are being made into a huge string with no /n. Do you know if there is a way to separate them within the program and if so how can I do it?
The file I'm working with can be downloaded in http://we.tl/YtixI1ck6l
and so far I was trying something like
ppi = []
for line in read_text:
prot_interaction = line[0:14]
ppi.append(prot_interaction)
result_ppi = []
for line in read_text:
result = line[-1]
result_ppi.append(result)
But since it's not formatted in lines but just in a single one I'm not getting any good results.
Using that file as an example, use the csv module to parse it.
Example:
import csv
with open('/tmp/Model_Oralome.txt', 'rU') as f:
reader=csv.reader(f, delimiter="\t")
for row in reader:
print row[0]
Prints:
ppi
C4FQL5;Q08426
C8PB60;D2NP19
P40189;Q05655
P22712;Q9NR31
...
P05783;P02751
B5E709;D2NPK7
Q8N7J2;Q9UKZ4
(BTW, the issue you may be having with this particular file is the line terminations are a CR only from a Mac Classic OS. You can fix that in Python by using the Universal Newline mode when you open the file...)
Excel is exporting the text file with carriage returns (\r) instead of newlines (\n).
ppi = []
with open("Model_Oralome.txt",'r') as f:
lines = f.readlines()
lines = lines[0].split('\r')
From here you can iterate through each line of lines. Since it looks like you want the value of the first column:
lines = lines[1:]
for line in lines:
content = line.split('\t')
ppi.append(content[0])
When I run the following in the Python IDLE Shell:
f = open(r"H:\Test\test.csv", "rb")
for line in f:
print line
#this works fine
however, when I run the following for a second time:
for line in f:
print line
#this does nothing
This does not work because you've already seeked to the end of the file the first time. You need to rewind (using .seek(0)) or re-open your file.
Some other pointers:
Python has a very good csv module. Do not attempt to implement CSV parsing yourself unless doing so as an educational exercise.
You probably want to open your file in 'rU' mode, not 'rb'. 'rU' is universal newline mode, which will deal with source files coming from platforms with different line endings for you.
Use with when working with file objects, since it will cleanup the handles for you even in the case of errors. Ex:
.
with open(r"H:\Test\test.csv", "rU") as f:
for line in f:
...
You can read the data from the file in a variable, and then you can iterate over this data any no. of times you want to in your script. This is better than doing seek back and forth.
f = open(r"H:\Test\test.csv", "rb")
data = f.readlines()
for line in data:
print line
for line in data:
print line
Output:
# This is test.csv
Line1,This is line 1, there are, some numbers here,321423423
Line2,This is line2 , there are some characters here,sdfdsfdsf
# This is test.csv
Line1,This is line 1, there are, some numbers here,321423423
Line2,This is line2 , there are some characters here,sdfdsfdsf
Because you've gone all the way through the CSV file, and the iterator is exhausted. You'll need to re-open it before the second loop.
I am new to Python programming...
I have a .txt file....... It looks like..
0,Salary,14000
0,Bonus,5000
0,gift,6000
I want to to replace the first '0' value to '1' in each line. How can I do this? Any one can help me.... With sample code..
Thanks in advance.
Nimmyliji
I know that you're asking about Python, but forgive me for suggesting that perhaps a different tool is better for the job. :) It's a one-liner via sed:
sed 's/^0,/1,/' yourtextfile.txt > output.txt
This applies the regex /^0,/ (which matches any 0, that occurs at the beginning of a line) to each line and replaces the matched text with 1, instead. The output is directed into the file output.txt specified.
inFile = open("old.txt", "r")
outFile = open("new.txt", "w")
for line in inFile:
outFile.write(",".join(["1"] + (line.split(","))[1:]))
inFile.close()
outFile.close()
If you would like something more general, take a look to Python csv module. It contains utilities for processing comma-separated values (abbreviated as csv) in files. But it can work with arbitrary delimiter, not only comma. So as you sample is obviously a csv file, you can use it as follows:
import csv
reader = csv.reader(open("old.txt"))
writer = csv.writer(open("new.txt", "w"))
writer.writerows(["1"] + line[1:] for line in reader)
To overwrite original file with new one:
import os
os.remove("old.txt")
os.rename("new.txt", "old.txt")
I think that writing to new file and then renaming it is more fault-tolerant and less likely corrupt your data than direct overwriting of source file. Imagine, that your program raised an exception while source file was already read to memory and reopened for writing. So you would lose original data and your new data wouldn't be saved because of program crash. In my case, I only lose new data while preserving original.
o=open("output.txt","w")
for line in open("file"):
s=line.split(",")
s[0]="1"
o.write(','.join(s))
o.close()
Or you can use fileinput with in place edit
import fileinput
for line in fileinput.FileInput("file",inplace=1):
s=line.split(",")
s[0]="1"
print ','.join(s)
f = open(filepath,'r')
data = f.readlines()
f.close()
edited = []
for line in data:
edited.append( '1'+line[1:] )
f = open(filepath,'w')
f.writelines(edited)
f.flush()
f.close()
Or in Python 2.5+:
with open(filepath,'r') as f:
data = f.readlines()
with open(outfilepath, 'w') as f:
for line in data:
f.write( '1' + line[1:] )
This should do it. I wouldn't recommend it for a truly big file though ;-)
What is going on (ex 1):
1: Open the file in read mode
2,3: Read all the lines into a list (each line is a separate index) and close the file.
4,5,6: Iterate over the list constructing a new list where each line has the first character replaced by a 1. The line[1:] slices the string from index 1 onward. We concatenate the 1 with the truncated list.
7,8,9: Reopen the file in write mode, write the list to the file (overwrite), flush the buffer, and close the file handle.
In Ex. 2:
I use the with statement that lets the file handle closing itself, but do essentially the same thing.