This is my code. What it should do is open the file called example.txt in the same directory and it should only print out the first word of a big list.
with open('example.txt') as file:
line = 'example.txt'
important_info = line.split()
print(important_info[0])
I'm pretty sure I messed up but I don't know how.
I first coded this and it worked
acc = ('info blah bloh blrjejw bfwe tee')
tui = acc.split()
print(tui[0])
In the code I showed above it only prints the first word for one line. But I want something that can do over 100 lines quickly. T think I'm close.
Want to make sure I understand- you want this program to read the first line of a file and print the first word right?
You're on the right track. You're accidentally splitting on the name of the file rather than it's file contents- you're missing the code that reads the contents of the file.
To explain your code:
with open('example.txt') as file:
line = 'example.txt'
important_info = line.split()
print(important_info[0])
( important_info is a list containing just the filename i.e. ['example.txt'] so printing the first element would just be the string example.txt )
Something like this would work (reading the first line, splitting it by whitespace so that it's a list of words and then printing the first word in that list)
f = open("example.txt", "r")
print(f.readline().split()[0])
You need to read the file:
with open('example.txt') as file:
line = file.read()
important_info = line.split()
print(important_info[0])
Related
I have a txt file that contains names which are separated by lines but with some empty lines.
When I execute the following code, every second name gets ommitted in the output array.
Why is that?
def get_string_list(string_textfile):
list = []
file = open("names.txt", "r")
for line in file:
line = file.readline()[:-1]
list.append(line.lower())
return list
when you iterate the file
for line in file:
# you read line just now it exists
line = file.readline()
# uh oh you just read another line... you didnt do anything with the first one
dont mix iteration of a file with readline in general (in fact i think modern python versions will throw an error if you try to mix these two)
if all you want is a list of lines you can do any of the following
lines = list(file)
# or
lines = file.readlines()
you can get only non_empty lines and strip newlines as follows
lines_stripped = list(filter(None,(l.strip() for l in file)))
not super pythonic but its nice and terse and pretty clear what its doing
modify for statements like following:
for line in file:
list.append(line.strip().lower())
list = [name for name in list if name]
last line added to remove empty line.
I have a text file which consists of many lines of text.
I would like to replace only the first line of a text file using python v3.6 regardless of the contents. I do not need to do a line-by-line search and replace the line accordingly. No duplication with question Search and replace a line in a file in Python
Here is my code;
import fileinput
file = open("test.txt", "r+")
file.seek(0)
file.write("My first line")
file.close()
The code works partially. If the original first line has string longer than "My first line", the excess sub-string still remains. To be clearer, if original line is "XXXXXXXXXXXXXXXXXXXXXXXXX", then the output will be "My first lineXXXXXXXXXXXXXX". I want the output to be only "My first line". Is there a better way to implement the code?
You can use the readlines and writelines to do this.
For example, I created a file called "test.txt" that contains two lines (in Out[3]). After opening the file, I can use f.readlines() to get all lines in a list of string format. Then, the only thing I need to do is to replace the first element of the string to whatever I want, and then write back.
with open("test.txt") as f:
lines = f.readlines()
lines # ['This is the first line.\n', 'This is the second line.\n']
lines[0] = "This is the line that's replaced.\n"
lines # ["This is the line that's replaced.\n", 'This is the second line.\n']
with open("test.txt", "w") as f:
f.writelines(lines)
Reading and writing content to the file is already answered by #Zhang.
I am just giving the answer for efficiency instead of reading all the lines.
Use: shutil.copyfileobj
from_file.readline() # and discard
to_file.write(replacement_line)
shutil.copyfileobj(from_file, to_file)
Reference
I am trying to write a python script to read in a large text file from some modeling results, grab the useful data and save it as a new array. The text file is output in a way that has a ## starting each line that is not useful. I need a way to search through and grab all the lines that do not include the ##. I am used to using grep -v in this situation and piping to a file. I want to do it in python!
Thanks a lot.
-Tyler
I would use something like this:
fh = open(r"C:\Path\To\File.txt", "r")
raw_text = fh.readlines()
clean_text = []
for line in raw_text:
if not line.startswith("##"):
clean_text.append(line)
Or you could also clean the newline and carriage return non-printing characters at the same time with a small modification:
for line in raw_text:
if not line.startswith("##"):
clean_text.append(line.rstrip("\r\n"))
You would be left with a list object that contains one line of required text per element. You could split this into individual words using string.split() which would give you a nested list per original list element which you could easily index (assuming your text has whitespaces of course).
clean_text[4][7]
would return the 5th line, 8th word.
Hope this helps.
[Edit: corrected indentation in loop]
My suggestion would be to do the following:
listoflines = [ ]
with open(.txt, "r") as f: # .txt = file, "r" = read
for line in f:
if line[:2] != "##": #Read until the second character
listoflines.append(line)
print listoflines
If you're feeling brave, you can also do the following, CREDITS GO TO ALEX THORNTON:
listoflines = [l for l in f if not l.startswith('##')]
The other answer is great as well, especially teaching the .startswith function, but I think this is the more pythonic way and also has the advantage of automatically closing the file as soon as you're done with it.
I am quite new to python and have just started importing text files. I have a text file which contains a list of words, I want to be able to enter a word and this word to be deleted from the text file. Can anyone explain how I can do this?
text_file=open('FILE.txt', 'r')
ListText = text_file.read().split(',')
DeletedWord=input('Enter the word you would like to delete:')
NewList=(ListText.remove(DeletedWord))
I have this so far which takes the file and imports it into a list, I can then delete a word from the new list but want to delete the word also from the text file.
Here's what I would recommend since its fairly simple and I don't think you're concerned with performance.:
f = open("file.txt",'r')
lines = f.readlines()
f.close()
excludedWord = "whatever you want to get rid of"
newLines = []
for line in lines:
newLines.append(' '.join([word for word in line.split() if word != excludedWord]))
f = open("file.txt", 'w')
for line in lines:
f.write("{}\n".format(line))
f.close()
This allows for a line to have multiple words on it, but it will work just as well if there is only one word per line
In response to the updated question:
You cannot directly edit the file (or at least I dont know how), but must instead get all the contents in Python, edit them, and then re-write the file with the altered contents
Another thing to note, lst.remove(item) will throw out the first instance of item in lst, and only the first one. So the second instance of item will be safe from .remove(). This is why my solution uses a list comprehension to exclude all instances of excludedWord from the list. If you really want to use .remove() you can do something like this:
while excludedWord in lst:
lst.remove(excludedWord)
But I would discourage this in favor for the equivalent list comprehension
We can replace strings in files (some imports needed;)):
import os
import sys
import fileinput
for line in fileinput.input('file.txt', inplace=1):
sys.stdout.write(line.replace('old_string', 'new_string'))
Find this (maybe) here: http://effbot.org/librarybook/fileinput.htm
If 'new_string' change to '', then this would be the same as to delete 'old_string'.
So I was trying something similar, here are some points to people whom might end up reading this thread. The only way you can replace the modified contents is by opening the same file in "w" mode. Then python just overwrites the existing file.
I tried this using "re" and sub():
import re
f = open("inputfile.txt", "rt")
inputfilecontents = f.read()
newline = re.sub("trial","",inputfilecontents)
f = open("inputfile.txt","w")
f.write(newline)
#Wnnmaw your code is a little bit wrong there it should go like this
f = open("file.txt",'r')
lines = f.readlines()
f.close()
excludedWord = "whatever you want to get rid of"
newLines = []
for line in newLines:
newLines.append(' '.join([word for word in line.split() if word != excludedWord]))
f = open("file.txt", 'w')
for line in lines:
f.write("{}\n".format(line))
f.close()
Hello I'm making a python program that takes in a file. I want this to be set to a single string. My current code is:
with open('myfile.txt') as f:
title = f.readline().strip();
content = f.readlines();
The text file (simplified) is:
Title of Document
asdfad
adfadadf
adfadaf
adfadfad
I want to strip the title (which my program does) and then make the rest one string. Right now the output is:
['asdfad\n', 'adfadadf\n', ect...]
and I want:
asdfadadfadadf ect...
I am new to python and I have spent some time trying to figure this out but I can't find a solution that works. Any help would be appreciated!
You can do this:
with open('/tmp/test.txt') as f:
title=f.next() # strip title line
data=''.join(line.rstrip() for line in f)
Use list.pop(0) to remove the first line from content.
Then str.join(iterable). You'll also need to strip off the newlines.
content.pop(0)
done = "".join([l.strip() for l in content])
print done
Another option is to read the entire file, then remove the newlines instead of joining together:
with open('somefile') as fin:
next(fin, None) # ignore first line
one_big_string = fin.read().replace('\n', '')
If you want the rest of the file in a single chunk, just call the read() function:
with open('myfile.txt') as f:
title = f.readline().strip()
content = f.read()
This will read the file until EOF is encountered.