Why am I getting an IndexError from a for loop? - python

I'm writing code that will take dates and numeric values from a csv file and compare them.
date_location = 3
numeric_location = 4
with open('file1.csv', 'r') as f1:
next(f1)
with open('file2.csv', 'r') as f2:
next(f2)
for i in (f1):
f1_date = (i.split()[date_location])
f1_number = (i.split()[numeric_location])
for j in (f2):
f2_date = (j.split()[date_location])
f2_number = (j.split()[numeric_location])
print(f1_date, f1_number)
print(f2_date, f2_number)
if f1_date == f2_date:
print(f1_date == f2_date)
if f2_number > f1_number:
print('WIN')
continue
elif f2_number <= f1_number:
print('lose')
f2.seek(0, 0)`
I get this error IndexError: list index out of range for f1_date = (i.split()[date_location]), which i assume will also affect:
f1_number = (i.split()[numeric_location])
f2_date = (j.split()[date_location])
f2_number = (j.split()[numeric_location])
Can anyone explain why? I haven't found a way to make it so this error doesn't show.
EDIT: I forgot to change the separator for .split() after messing around with the for loop using text files

Two main possibilities:
1) Your csv files are not space delimited, and as the default separator for .split() is " ", you will not have at least 4 space-separated items in i.split() (or 5 for numeric_location).
2) Your csv is space delimited, but is ragged, i.e. it has incomplete rows, so for some row, there is no data for column 4.
I also highly suggest using a library for reading csvs. csv is in the standard library, and pandas has built-in handling of ragged lines.

f1_number = (i.split()[numeric_location])
This is doing a lot in a single line. I suggest you split this into two lines:
f1 = i.split()
f1_number = f1[numeric_location]
f1_date = f1[date_location]
Now you will see which of these causes the problem. You should add a print(f1) to see the value after the split. Most likely it doesn't have as many elements as you think it does. Or your indexes are off from what they should be.

The call to i.split() is going to generate a new list, which will contain each word of the from the string i. So
"this is an example".split() == ["this", "is", "an", "example"]
You are trying to access the third element of the resulting list, and the index error tells you that this list has less than four members. I suggest printing the result of i.split(). Very likely this is either an off by one error, or the first line of your file contains something different than what you are expecting.
Also split() by default will split on whitespace, given that you have a csv you may have wanted to do split(',').

The error is happening because you only have one element in the case of i.split()
But date_location is equal to 3.
You need to add a separator based on your csv file in the str.split method.
You can read more about it here

Related

Python split tabspaced bilingual txt to two separate txt files (list) with newlines separating strings

I have a bi-lingual corpora (EN-JP) from tatoeba and want to split this into two separate files. The strings have to say on the same line respectively.
I need this for training an NMT in nmt-keras and training data has to be stored in separate files for each language. I tried several approaches, but since I'm an absolute beginner with python and coding in general I feel like I'm running in circles.
So far the best I managed was the following:
Source txt:
Go. 行け。
Go. 行きなさい。
Hi. やっほー。
Hi. こんにちは!
Code:
with open('jpns.txt', encoding="utf8") as f:
columns = zip(*(l.split("\t") for l in f))
list1= list(columns)
print(list1)
[('Go.', 'Go.', 'Hi.', 'Hi.'), ('行け。\n', '行きなさい。\n', 'やっほー。\n', 'こんにちは!')]
Result with my code:
[('Go.', 'Go.', 'Hi.', 'Hi.'), ('行け。\n', '行きなさい。\n', 'やっほー。\n', 'こんにちは!')]
English and Japanese get properly separated (into a Tuple?) but I'm stuck at figuring out how to export only English and how to export only Japanese to an output.en and an output.jp respecitvely.
Expected result:
output.en
Go.
Go.
Hi.
Hi.
output.jp
行け。
行きなさい。
やっほー。
こんにちは!
Each outputted strings should contain an \n after the string.
Please keep in mind that I'm a total beginner with coding, so I'm not exactly sure what I did after "zip" as I just found this here on stackoverflow. I'd be really gratful for a fully commented suggestion.
The first thing to be aware of is that iterating over a file retains the newlines. That means that in your two columns, the first has no newlines, while the second has newlines already appended to each line (except possibly the last).
Writing the second column is therefore trivial if you've already unpacked the generator columns:
with open('output.jp', 'w') as f:
f.writelines(list1[-1])
But you still have to append newlines to the first column (and possibly others if you go full-on multilingual). One way would be to append newlines to all the columns but the last. Another would be to strip the columns from the last column and process all of them the same.
You can achieve the result you want with a small loop, and another call to zip:
langs = ('en', 'jp')
for index, (lang, data) in enumerate(zip(langs, columns)):
with open('output.' + lang, 'w') as f:
if index < len(langs) - 1:
data = (line + '\n' for line in data)
f.writelines(data)
This approach replaces the tuple data with a generator that appends newlines, unless we are at the last column.
There are a couple of ways to insert newlines between each line in the output files. The one I show uses a lazy generator to append to each line individually. This should save a little memory. If you don't care about memory savings, you can output the whole file as a single string:
joiner = '\n' if index < len(langs) - 1 else ''
f.write(joiner.join(data))
You can even write the loop yourself and print to the file:
for line in data:
print(line, file=f, end='\n' if index < len(args) - 1 else '')
Addendum
Let's also look at the line columns = zip(*(l.split("\t") for l in f)) in detail, since it is a very common Python idiom for transposing nested lists, and is the key to getting the result you want.
The generator expression l.split("\t") for l in f is pretty straightforward: it splits each line in the file around tabs, giving you two elements, one in English, and one in Japanese. Adding a * in front of the generator expands it so that each two-element row becomes a separate argument to zip. zip then re-combines the respective elements of each row, so you get a column of the English elements, and a column of the Japanese elements, effectively transposing your original "matrix".
The result is that columns is a generator over the columns. You can convert it to a list, but that is only necessary for viewing. The generator will work fine for the code shown above.

How to import a special format as a dictionary in python?

I have the text files as below format in single line,
username:password;username1:password1;username2:password2;
etc.
What I have tried so far is
with open('list.txt') as f:
d = dict(x.rstrip().split(None, 1) for x in f)
but I get an error saying that the length is 1 and 2 is required which indicates the file is not being as key:value.
Is there any way to fix this or should I just reformat the file in another way?
thanks for your answers.
What i got so far is:
with open('tester.txt') as f:
password_list = dict(x.strip(":").split(";", 1) for x in f)
for user, password in password_list.items():
print(user + " - " + password)
the results comes out as username:password - username1:password1
what i need is to split username:password where key = user and value = password
Since variable f in this case is a file object and not a list, the first thing to do would be to get the lines from it. You could use the https://docs.python.org/2/library/stdtypes.html?highlight=readline#file.readlines* method for this.
Furthermore, I think I would use strip with the semicolon (";") parameter. This will provide you with a list of strings of "username:password", provided your entire file looks like this.
I think you will figure out what to do after that.
EDIT
* I auto assumed you use Python 2.7 for some reason. In version 3.X you might want to look at the "distutils.text_file" (https://docs.python.org/3.7/distutils/apiref.html?highlight=readlines#distutils.text_file.TextFile.readlines) class.
Load the text of the file in Python with open() and read() as a string
Apply split(;) to that string to create a list like [username:password, username1:password1, username2:password2]
Do a dict comprehension where you apply split(":") to each item of the above list to split those pairs.
with open('list.txt', 'rt') as f:
raw_data = f.readlines()[0]
list_data = raw_data.split(';')
user_dict = { x.split(':')[0]:x.split(':')[1] for x in list_data }
print(user_dict)
Dictionary comprehension is useful here.
One liner to pull all the info out of the text file. As requested. Hope your tutor is impressed. Ask him How it works and see what he says. Maybe update your question to include his response.
If you want me to explain, feel free to comment and I shall go into more detail.
The error you're probably getting:
ValueError: dictionary update sequence element #3 has length 1; 2 is required
is because the text line ends with a semicolon. Splitting it on semicolons then results in a list that contains some pairs, and an empty string:
>>> "username:password;username1:password1;username2:password2;".split(";")
['username:password', 'username1:password1', 'username2:password2', '']
Splitting the empty string on colons then results in a single empty string, rather than two strings.
To fix this, filter out the empty string. One example of doing this would be
[element for element in x.split(";") if element != ""]
In general, I recommend you do the work one step at a time and assign to intermediary variables.
Here's a simple (but long) answer. You need to get the line from the file, and then split it and the items resulting from the split:
results = {}
with open('file.txt') as file:
for line in file:
#Only one line, but that's fine
entries = line.split(';')
for entry in entries:
if entry != '':
#The last item in entries will be blank, due to how split works in this example
user, password = entry.split(':')
results[user] = password
Try this.
f = open('test.txt').read()
data = f.split(";")
d = {}
for i in data:
if i:
value = i.split(":")
d.update({value[0]:value[1]})
print d

Having problems with strings and arrays

I want to read a text file and copy text that is in between '~~~~~~~~~~~~~' into an array. However, I'm new in Python and this is as far as I got:
with open("textfile.txt", "r",encoding='utf8') as f:
searchlines = f.readlines()
a=[0]
b=0
for i,line in enumerate(searchlines):
if '~~~~~~~~~~~~~' in line:
b=b+1
if '~~~~~~~~~~~~~' not in line:
if 's1mb4d' in line:
break
a.insert(b,line)
This is what I envisioned:
First I read all the lines of the text file,
then I declare 'a' as an array in which text should be added,
then I declare 'b' because I need it as an index. The number of lines in between the '~~~~~~~~~~~~~' is not even, that's why I use 'b' so I can put lines of text into one array index until a new '~~~~~~~~~~~~~' was found.
I check for '~~~~~~~~~~~~~', if found I increase 'b' so I can start adding lines of text into a new array index.
The text file ends with 's1mb4d', so once its found, the program ends.
And if '~~~~~~~~~~~~~' is not found in the line, I add text to the array.
But things didn't go well. Only 1 line of the entire text between those '~~~~~~~~~~~~~' is being copied to the each array index.
Here is an example of the text file:
~~~~~~~~~~~~~
Text123asdasd
asdasdjfjfjf
~~~~~~~~~~~~~
123abc
321bca
gjjgfkk
~~~~~~~~~~~~~
You could use regex expression, give a try to this:
import re
input_text = ['Text123asdasd asdasdjfjfjf','~~~~~~~~~~~~~','123abc 321bca gjjgfkk','~~~~~~~~~~~~~']
a = []
for line in input_text:
my_text = re.findall(r'[^\~]+', line)
if len(my_text) != 0:
a.append(my_text)
What it does is it reads line by line looks for all characters but '~' if line consists only of '~' it ignores it, every line with text is appended to your a list afterwards.
And just because we can, oneliner (excluding import and source ofc):
import re
lines = ['Text123asdasd asdasdjfjfjf','~~~~~~~~~~~~~','123abc 321bca gjjgfkk','~~~~~~~~~~~~~']
a = [re.findall(r'[^\~]+', line) for line in lines if len(re.findall(r'[^\~]+', line)) != 0]
In python the solution to a large part of problems is often to find the right function from the standard library that does the job. Here you should try using split instead, it should be way easier.
If I understand correctly your goal, you can do it like that :
joined_lines = ''.join(searchlines)
result = joined_lines.split('~~~~~~~~~~')
The first line joins your list of lines into a sinle string, and then the second one cut that big string every times it encounters the '~~' sequence.
I tried to clean it up to the best of my knowledge, try this and let me know if it works. We can work together on this!:)
with open("textfile.txt", "r",encoding='utf8') as f:
searchlines = f.readlines()
a = []
currentline = ''
for i,line in enumerate(searchlines):
currentline += line
if '~~~~~~~~~~~~~' in line:
a.append(currentline)
elif 's1mb4d' in line:
break
Some notes:
You can use elif for your break function
Append will automatically add the next iteration to the end of the array
currentline will continue to add text on each line as long as it doesn't have 's1mb4d' or the ~~~ which I think is what you want
s = ['']
with open('path\\to\\sample.txt') as f:
for l in f:
a = l.strip().split("\n")
s += a
a = []
for line in s:
my_text = re.findall(r'[^\~]+', line)
if len(my_text) != 0:
a.append(my_text)
print a
>>> [['Text123asdasd asdasdjfjfjf'], ['123abc 321bca gjjgfkk']]
If you're willing to impose/accept the constraint that the separator should be exactly 13 ~ characters (actually '\n%s\n' % ( '~' * 13) to be specific) ...
then you could accomplish this for relatively normal sized files using just
#!/usr/bin/python
## (Should be #!/usr/bin/env python; but StackOverflow's syntax highlighter?)
separator = '\n%s\n' % ('~' * 13)
with open('somefile.txt') as f:
results = f.read().split(separator)
# Use your results, a list of the strings separated by these separators.
Note that '~' * 13 is a way, in Python, of constructing a string by repeating some smaller string thirteen times. 'xx%sxx' % 'YY' is a way to "interpolate" one string into another. Of course you could just paste the thirteen ~ characters into your source code ... but I would consider constructing the string as shown to make it clear that the length is part of the string's specification --- that this is part of your file format requirements ... and that any other number of ~ characters won't be sufficient.
If you really want any line of any number of ~ characters to serve as a separator than you'll want to use the .split() method from the regular expressions module rather than the .split() method provided by the built-in string objects.
Note that this snippet of code will return all of the text between your separator lines, including any newlines they include. There are other snippets of code which can filter those out. For example given our previous results:
# ... refine results by filtering out newlines (replacing them with spaces)
results = [' '.join(each.split('\n')) for each in results]
(You could also use the .replace() string method; but I prefer the join/split combination). In this case we're using a list comprehension (a feature of Python) to iterate over each item in our results, which we're arbitrarily naming each), performing our transformation on it, and the resulting list is being boun back to the name results; I highly recommend learning and getting comfortable with list comprehension if you're going to learn Python. They're commonly used and can be a bit exotic compared to the syntax of many other programming and scripting languages).
This should work on MS Windows as well as Unix (and Unix-like) systems because of how Python handles "universal newlines." To use these examples under Python 3 you might have to work a little on the encodings and string types. (I didn't need to for my Python3.6 installed under MacOS X using Homebrew ... but just be forewarned).

Writing from one file to another

I've been stuck on this Python homework problem for awhile now: "Write a complete python program that reads 20 real numbers from a file inner.txt and outputs them in sorted order to a file outter.txt."
Alright, so what I do is:
f=open('inner.txt','r')
n=f.readlines()
n.replace('\n',' ')
n.sort()
x=open('outter.txt','w')
x.write(print(n))
So my thought process is: Open the text file, n is the list of read lines in it, I replace all the newline prompts in it so it can be properly sorted, then I open the text file I want to write to and print the list to it. First problem is it won't let me replace the new line functions, and the second problem is I can't write a list to a file.
I just tried this:
>>> x= "34\n"
>>> print(int(x))
34
So, you shouldn't have to filter out the "\n" like that, but can just put it into int() to convert it into an integer. This is assuming you have one number per line and they're all integers.
You then need to store each value into a list. A list has a .sort() method you can use to then sort the list.
EDIT:
forgot to mention, as other have already said, you need to iterate over the values in n as it's a list, not a single item.
Here's a step by step solution that fixes the issues you have :)
Opening the file, nothing wrong here.
f=open('inner.txt','r')
Don't forget to close the file:
f.close()
n is now a list of each line:
n=f.readlines()
There are no list.replace methods, so I suggest changing the above line to n = f.read(). Then, this will work (don't forget to reassign n, as strings are immutable):
n = n.replace('\n','')
You still only have a string full of numbers. However, instead of replacing the newline character, I suggest splitting the string using the newline as a delimiter:
n = n.split('\n')
Then, convert these strings to integers:
`n = [int(x) for x in n]`
Now, these two will work:
n.sort()
x=open('outter.txt','w')
You want to write the numbers themselves, so use this:
x.write('\n'.join(str(i) for i in n))
Finally, close the file:
x.close()
Using a context manager (the with statement) is good practice as well, when handling files:
with open('inner.txt', 'r') as f:
# do stuff with f
# automatically closed at the end
I guess real means float. So you have to convert your results to float to sort properly.
raw_lines = f.readlines()
floats = map(float, raw_lines)
Then you have to sort it. To write result back, you have to convert to string and join with line endings:
sortеd_as_string = map(str, sorted_floats)
result = '\n'.join(sortеd_as_string)
Finally you have have to write result to destination.
Ok let's look it step by step what you want to do.
First: Read some integers out of a textfile.
Pythonic Version:
fileNumbers = [int(line) for line in open(r'inner.txt', 'r').readlines()]
Easy to get version:
fileNumbers = list()
with open(r'inner.txt', 'r') as fh:
for singleLine in fh.readlines():
fileNumbers.append(int(singleLine))
What it does:
Open the file
Read each line, convert it to int (because readlines return string values) and append it to the list fileNumbers
Second: Sort the list
fileNumbers.sort()
What it does:
The sort function sorts the list by it's value e.g. [5,3,2,4,1] -> [1,2,3,4,5]
Third: Write it to a new textfile
with open(r'outter.txt', 'a') as fh:
[fh.write('{0}\n'.format(str(entry))) for entry in fileNumbers]

Trouble sorting a list with python

I'm somewhat new to python. I'm trying to sort through a list of strings and integers. The lists contains some symbols that need to be filtered out (i.e. ro!ad should end up road). Also, they are all on one line separated by a space. So I need to use 2 arguments; one for the input file and then the output file. It should be sorted with numbers first and then the words without the special characters each on a different line. I've been looking at loads of list functions but am having some trouble putting this together as I've never had to do anything like this. Any takers?
So far I have the basic stuff
#!/usr/bin/python
import sys
try:
infilename = sys.argv[1] #outfilename = sys.argv[2]
except:
print "Usage: ",sys.argv[0], "infile outfile"; sys.exit(1)
ifile = open(infilename, 'r')
#ofile = open(outfilename, 'w')
data = ifile.readlines()
r = sorted(data, key=lambda item: (int(item.partition(' ')[0])
if item[0].isdigit() else float('inf'), item))
ifile.close()
print '\n'.join(r)
#ofile.writelines(r)
#ofile.close()
The output shows exactly what was in the file but exactly as the file is written and not sorted at all. The goal is to take a file (arg1.txt) and sort it and make a new file (arg2.txt) which will be cmd line variables. I used print in this case to speed up the editing but need to have it write to a file. That's why the output file areas are commented but feel free to tell me I'm stupid if I screwed that up, too! Thanks for any help!
When you have an issue like this, it's usually a good idea to check your data at various points throughout the program to make sure it looks the way you want it to. The issue here seems to be in the way you're reading in the file.
data = ifile.readlines()
is going to read in the entire file as a list of lines. But since all the entries you want to sort are on one line, this list will only have one entry. When you try to sort the list, you're passing a list of length 1, which is going to just return the same list regardless of what your key function is. Try changing the line to
data = ifile.readlines()[0].split()
You may not even need the key function any more since numbers are placed before letters by default. I don't see anything in your code to remove special characters though.
since they are on the same line you dont really need readlines
with open('some.txt') as f:
data = f.read() #now data = "item 1 item2 etc..."
you can use re to filter out unwanted characters
import re
data = "ro!ad"
fixed_data = re.sub("[!?#$]","",data)
partition maybe overkill
data = "hello 23frank sam wilbur"
my_list = data.split() # ["hello","23frank","sam","wilbur"]
print sorted(my_list)
however you will need to do more to force numbers to sort maybe something like
numbers = [x for x in my_list if x[0].isdigit()]
strings = [x for x in my_list if not x[0].isdigit()]
sorted_list = sorted(numbers,key=lambda x:int(re.sub("[^0-9]","",x))) + sorted(strings(
Also, they are all on one line separated by a space.
So your file contains a single line?
data = ifile.readlines()
This makes data into a list of the lines in your file. All 1 of them.
r = sorted(...)
This makes r the sorted version of that list.
To get the words from the line, you can .read() the entire file as a single string, and .split() it (by default, it splits on whitespace).

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