When opening a file and concatenating the 5th character from each string, I'm getting duplicates of each character in the new string. How can I fix this?
def fifthchar(filename):
l=""
fin=open(filename, "r")
for line in fin:
line=line.strip()
line=str(line)
for i in line:
if len(line)>=5:
a=line[4]
l+=a
fin.close()
return l
def fifthchar(filename):
l=''
lines = []
fin=open(filename, 'r')
all_lines = fin.read().decode("utf-8-sig").encode("utf-8")
lines = all_lines.splitlines()
line =''
for line in lines:
line=str(line)
line=line.strip()
print line
if len(line)>=5:
a=line[4]
l+=a
fin.close()
return l
if __name__ == '__main__':
print fifthchar("read_lines.txt")
if you want to reamove the withe space from the beginig and the end use
line = line.strip()
if you want to remove the all whitespace from the string use
line = line.replace(" ","")
this line automatically removes the expected BOM.
all_lines = fin.read().decode("utf-8-sig").encode("utf-8")
for details
hope this will help.
Just remove this unnecessary line and indent accordingly:
for i in line:
You were doing concatenation for each character in line due to this reason.
Related
In Python, calling e.g. temp = open(filename,'r').readlines() results in a list in which each element is a line from the file. However, these strings have a newline character at the end, which I don't want.
How can I get the data without the newlines?
You can read the whole file and split lines using str.splitlines:
temp = file.read().splitlines()
Or you can strip the newline by hand:
temp = [line[:-1] for line in file]
Note: this last solution only works if the file ends with a newline, otherwise the last line will lose a character.
This assumption is true in most cases (especially for files created by text editors, which often do add an ending newline anyway).
If you want to avoid this you can add a newline at the end of file:
with open(the_file, 'r+') as f:
f.seek(-1, 2) # go at the end of the file
if f.read(1) != '\n':
# add missing newline if not already present
f.write('\n')
f.flush()
f.seek(0)
lines = [line[:-1] for line in f]
Or a simpler alternative is to strip the newline instead:
[line.rstrip('\n') for line in file]
Or even, although pretty unreadable:
[line[:-(line[-1] == '\n') or len(line)+1] for line in file]
Which exploits the fact that the return value of or isn't a boolean, but the object that was evaluated true or false.
The readlines method is actually equivalent to:
def readlines(self):
lines = []
for line in iter(self.readline, ''):
lines.append(line)
return lines
# or equivalently
def readlines(self):
lines = []
while True:
line = self.readline()
if not line:
break
lines.append(line)
return lines
Since readline() keeps the newline also readlines() keeps it.
Note: for symmetry to readlines() the writelines() method does not add ending newlines, so f2.writelines(f.readlines()) produces an exact copy of f in f2.
temp = open(filename,'r').read().split('\n')
Reading file one row at the time. Removing unwanted chars from end of the string with str.rstrip(chars).
with open(filename, 'r') as fileobj:
for row in fileobj:
print(row.rstrip('\n'))
See also str.strip([chars]) and str.lstrip([chars]).
I think this is the best option.
temp = [line.strip() for line in file.readlines()]
temp = open(filename,'r').read().splitlines()
My preferred one-liner -- if you don't count from pathlib import Path :)
lines = Path(filename).read_text().splitlines()
This it auto-closes the file, no need for with open()...
Added in Python 3.5.
https://docs.python.org/3/library/pathlib.html#pathlib.Path.read_text
Try this:
u=open("url.txt","r")
url=u.read().replace('\n','')
print(url)
To get rid of trailing end-of-line (/n) characters and of empty list values (''), try:
f = open(path_sample, "r")
lines = [line.rstrip('\n') for line in f.readlines() if line.strip() != '']
You can read the file as a list easily using a list comprehension
with open("foo.txt", 'r') as f:
lst = [row.rstrip('\n') for row in f]
my_file = open("first_file.txt", "r")
for line in my_file.readlines():
if line[-1:] == "\n":
print(line[:-1])
else:
print(line)
my_file.close()
This script here will take lines from file and save every line without newline with ,0 at the end in file2.
file = open("temp.txt", "+r")
file2 = open("res.txt", "+w")
for line in file:
file2.writelines(f"{line.splitlines()[0]},0\n")
file2.close()
if you looked at line, this value is data\n, so we put splitlines()
to make it as an array and [0] to choose the only word data
import csv
with open(filename) as f:
csvreader = csv.reader(f)
for line in csvreader:
print(line[0])
In Python, calling e.g. temp = open(filename,'r').readlines() results in a list in which each element is a line from the file. However, these strings have a newline character at the end, which I don't want.
How can I get the data without the newlines?
You can read the whole file and split lines using str.splitlines:
temp = file.read().splitlines()
Or you can strip the newline by hand:
temp = [line[:-1] for line in file]
Note: this last solution only works if the file ends with a newline, otherwise the last line will lose a character.
This assumption is true in most cases (especially for files created by text editors, which often do add an ending newline anyway).
If you want to avoid this you can add a newline at the end of file:
with open(the_file, 'r+') as f:
f.seek(-1, 2) # go at the end of the file
if f.read(1) != '\n':
# add missing newline if not already present
f.write('\n')
f.flush()
f.seek(0)
lines = [line[:-1] for line in f]
Or a simpler alternative is to strip the newline instead:
[line.rstrip('\n') for line in file]
Or even, although pretty unreadable:
[line[:-(line[-1] == '\n') or len(line)+1] for line in file]
Which exploits the fact that the return value of or isn't a boolean, but the object that was evaluated true or false.
The readlines method is actually equivalent to:
def readlines(self):
lines = []
for line in iter(self.readline, ''):
lines.append(line)
return lines
# or equivalently
def readlines(self):
lines = []
while True:
line = self.readline()
if not line:
break
lines.append(line)
return lines
Since readline() keeps the newline also readlines() keeps it.
Note: for symmetry to readlines() the writelines() method does not add ending newlines, so f2.writelines(f.readlines()) produces an exact copy of f in f2.
temp = open(filename,'r').read().split('\n')
Reading file one row at the time. Removing unwanted chars from end of the string with str.rstrip(chars).
with open(filename, 'r') as fileobj:
for row in fileobj:
print(row.rstrip('\n'))
See also str.strip([chars]) and str.lstrip([chars]).
I think this is the best option.
temp = [line.strip() for line in file.readlines()]
temp = open(filename,'r').read().splitlines()
My preferred one-liner -- if you don't count from pathlib import Path :)
lines = Path(filename).read_text().splitlines()
This it auto-closes the file, no need for with open()...
Added in Python 3.5.
https://docs.python.org/3/library/pathlib.html#pathlib.Path.read_text
Try this:
u=open("url.txt","r")
url=u.read().replace('\n','')
print(url)
To get rid of trailing end-of-line (/n) characters and of empty list values (''), try:
f = open(path_sample, "r")
lines = [line.rstrip('\n') for line in f.readlines() if line.strip() != '']
You can read the file as a list easily using a list comprehension
with open("foo.txt", 'r') as f:
lst = [row.rstrip('\n') for row in f]
my_file = open("first_file.txt", "r")
for line in my_file.readlines():
if line[-1:] == "\n":
print(line[:-1])
else:
print(line)
my_file.close()
This script here will take lines from file and save every line without newline with ,0 at the end in file2.
file = open("temp.txt", "+r")
file2 = open("res.txt", "+w")
for line in file:
file2.writelines(f"{line.splitlines()[0]},0\n")
file2.close()
if you looked at line, this value is data\n, so we put splitlines()
to make it as an array and [0] to choose the only word data
import csv
with open(filename) as f:
csvreader = csv.reader(f)
for line in csvreader:
print(line[0])
I've learned that we can easily remove blank lined in a file or remove blanks for each string line, but how about remove all blanks at the end of each line in a file ?
One way should be processing each line for a file, like:
with open(file) as f:
for line in f:
store line.strip()
Is this the only way to complete the task ?
Possibly the ugliest implementation possible but heres what I just scratched up :0
def strip_str(string):
last_ind = 0
split_string = string.split(' ')
for ind, word in enumerate(split_string):
if word == '\n':
return ''.join([split_string[0]] + [ ' {} '.format(x) for x in split_string[1:last_ind]])
last_ind += 1
Don't know if these count as different ways of accomplishing the task. The first is really just a variation on what you have. The second does the whole file at once, rather than line-by-line.
Map that calls the 'rstrip' method on each line of the file.
import operator
with open(filename) as f:
#basically the same as (line.rstrip() for line in f)
for line in map(operator.methodcaller('rstrip'), f)):
# do something with the line
read the whole file and use re.sub():
import re
with open(filename) as f:
text = f.read()
text = re.sub(r"\s+(?=\n)", "", text)
You just want to remove spaces, another solution would be...
line.replace(" ", "")
Good to remove white spaces.
I want to replace a line in a file but my code doesn't do what I want. The code doesn't change that line. It seems that the problem is the space between ALS and 4277 characters in the input.txt. I need to keep that space in the file. How can I fix my code?
A part part of input.txt:
ALS 4277
Related part of the code:
for lines in fileinput.input('input.txt', inplace=True):
print(lines.rstrip().replace("ALS"+str(4277), "KLM" + str(4945)))
Desired output:
KLM 4945
Using the same idea that other user have already pointed out, you could also reproduce the same spacing, by first matching the spacing and saving it in a variable (spacing in my code):
import re
with open('input.txt') as f:
lines = f.read()
match = re.match(r'ALS(\s+)4277', lines)
if match != None:
spacing = match.group(1)
lines = re.sub(r'ALS\s+4277', 'KLM%s4945'%spacing, lines.rstrip())
print lines
As the spaces vary you will need to use regex to account for the spaces.
import re
lines = "ALS 4277 "
line = re.sub(r"(ALS\s+4277)", "KLM 4945", lines.rstrip())
print(line)
Try:
with open('input.txt') as f:
for line in f:
a, b = line.strip().split()
if a == 'ALS' and b == '4277':
line = line.replace(a, 'KLM').replace(b, '4945')
print(line, end='') # as line has '\n'
I want to strip spaces to single space but preserve one empty line separator in a file. I have tried the following code and it seems to work.
How can I do this with out writing to the file twice?
I want to collect all my substitutions may be in a text file and write them all at once.
i = open('inputfile.txt','r')
infile = i.readlines()
o = open('outputfile.txt','w')
for line in infile:
if line == '\n':
o.write('\n\n')
else:
o.write(re.sub(r'\s+',' ',line))
o.close()
i.close()
See my answer in this question here: Python save file to csv
I think the re.sub() replacement is tripping you up with the '\s' value. Just replace ' ' instead.
i = open('inputfile.txt','r')
infile = i.readlines()
o = open('outputfile.txt','w')
newoutputfile = ""
for line in infile:
if line == '\n':
newoutputfile+= '\n\n'
else:
newoutputfile +=' '.join(line.split())
o.write(newoutputfile)
o.close()