I have a .txt file with 20 lines. Each line carrying 10 zeroes separated by comma.
0,0,0,0,0,0,0,0,0,0
I want to replace every fifth 0 with 1 in each line. I tried .replace function but I know there must be some easy way in python
You can split the text string with the below command.
text_string="0,0,0,0,0,0,0,0,0,0"
string_list= text_string.split(",")
Then you can replace every fifth element in the list string_list using insert command.
for i in range(4,len(string_list),5):
string_list.insert(i,"1")
After this join the elements of the list using join method
output = "".join([str(i)+"," for i in string_list])
The output for this will be :
'0,0,0,0,1,0,0,0,0,1,0,0,'
This is one way of doing
If text in this File follows some rule, you can parse it as CSV file, and change every fifth index and rewrite it to a new file.
But if you want to modify the existing text file, like replace the character then you can use seek refer to How to modify a text file?
Related
I have a text file which contains a table comprised of numbers e.g:
5,10,6
6,20,1
7,30,4
8,40,3
9,23,1
4,13,6
if for example I want the numbers contained only in the third column, how do i extract that column into a list?
I have tried the following:
myNumbers.append(line.split(',')[2])
The strip method will make sure that the newline character is stripped off. The split method is used here to make sure that the commas are used as a delimiter.
line.strip().split(',')[2]
I have a very long .txt file of bbcoded data. I've split each sampling of data into a separate item in a list:
import re
file = open('scratch.txt', 'r')
file = file.read()
# split each dial into a separate entry in list
alldials = file.split('\n\n')
adials = []i
for dial in alldials:
re.split('b|d|c', dial)
adials.append(dial)
print(adials[1])
print(adials[1][8])
so that prints a string of data and the 9th character in the string. But the string is not split by the letters used in the argument, or really split at all unless the print command specifically asks for that second index....
what I'd like to split it by are these strings: '\s\s[b]', '[\b]', [dial], [\dial], [icon], and [\icon], but as I started running into problems, I simplified the code down more and more, to figure out what was going wrong, and now I'm as simple as I can make it and I guess I'm missunderstanding a fundamental part of split() or the re module.
the problem is that re.split does not modify the string in place, it returns it as a new string, which means if you want to split it you should do something like this:
split_dial = re.split('b|d|c', dial)
adials.append(split_dial)
So I'm trying to retrieve all male members from a name list, it looks something like this: A B(male) C D E(male) F(male) G
All strings are separated with space. The name list is saved as a txt file: name.txt
I would like to have Python to read in name.txt and retrieve all males from the list, then print them out (in this case B E and F).
How do I use regular expression to achieve that? Thanks!
I am just giving the regex expression, regex = r"(\w+)\(male\)"
It's apparently some data. Why are you storing and retrieving it from a text file?
If it's some temp data being stored in a text file maybe change the formatting and specify both 'Male' and 'Female' and also one entry per line so you can loop through the file?
That'll be more systematic.
So all you'll have to do is look for a string match for 'Male' in every line and select that line to print.
how can I read once at a time 2 strings from a txt file, that are written on the same line?
e.g.
francesco 10
# out is your file
out.readline().split() # result is ['francesco', '10']
Assuming that your two strings are separated by whitespace. You can split based on any string (comma, colon, etc.)
Why not read just the line and split it up later? You'd have to read byte-by-byte and look for the space character, which is very inefficient. Better to read the entire line, and then split the resulting string on the space, giving you two strings.
'francesco 10'.split()
will give you ['francesco', '10'].
for line in fi:
line.split()
Its ideal to just iterate over a file object.
I have a list of horizontal names that is too long to open in excel. It's 90,000 names long. I need to add a comma after each name to put into my program. I tried find/replace but it freezes up my computer and crashes. Is there a clever way I can get a comma at the end of each name? My options to work with are python and excel thanks.
If you actually had a Python list, say names, then ','.join(names) would make into a string with a comma between each name and the following one (if you need one at the end as well, just use + ',' to append one more comma to the result).
Even though you say you have "a list" I suspect you actually have a string instead, for example in a file, where the names are separated by...? You don't tell us, and therefore force us to guess. For example, if they're separated by line-ends (one name per line), your life is easiest:
with open('yourfile.txt') as f:
result = ','.join(f)
(again, supplement this with a + ',' after the join if you need that, of course). That's because separation by line-ends is the normal default behavior for a text file, of course.
If the separator is something different, you'll have to read the file's contents as a string (with f.read()) and split it up appropriately then join it up again with commas.
For example, if the separator is a tab character:
with open('yourfile.txt') as f:
result = ','.join(f.read().split('\t'))
As you see, it's not so much worse;-).