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For a school assignment
we want to convert every item in the list to be an int using the int(val) function. This will involve first reading in the file, loading all the lines, and then looping through all lines building a second list of ints (use lst). You should return the list of ints
but I don't know how to do it.
This is what I have so far.
def file_int_list(file):
with open(file, 'r+') as f:
lst = []
lines = f.readlines()
for rows in lines:
lst.append(rows)
return lst
lst = []
lines = f.readlines()
for rows in lines:
lst.extend(list(map(int, rows.split(' '))))
return lst
I'm currently working on a program that takes a group of lists from a csv file, and groups them together. The program I came up with is:
List_one = []
with open("trees.csv") as f:
skiplines = f.readline()
for line in f:
res = line.split(" ")
List_one.append(res)
for i in List_one:
(i[0]) = (i[0]).rstrip("\n")
print (List_one)
What I get now are a group of lists, but the problem is that these lists are strings and I want them as floats. The lists look like this:
[['1,8.3,70,10.3'], ['2,8.6,65,10.3'], ['3,8.8,63,10.2'], ['4,10.5,72,16.4'], ['5,10.7,81,18.8'], ['6,10.8,83,19.7'], ['7,11.0,66,15.6'], ['8,11.0,75,18.2'], ['9,11.1,80,22.6'], ['10,11.2,75,19.9'], ['11,11.3,79,24.2'], ['12,11.4,76,21.0'], ['13,11.4,76,21.4'], ['14,11.7,69,21.3'], ['15,12.0,75,19.1'], ['16,12.9,74,22.2'], ['17,12.9,85,33.8'], ['18,13.3,86,27.4'], ['19,13.7,71,25.7'], ['20,13.8,64,24.9'], ['21,14.0,78,34.5'], ['22,14.2,80,31.7'], ['23,14.5,74,36.3'], ['24,16.0,72,38.3'], ['25,16.3,77,42.6'], ['26,17.3,81,55.4'], ['27,17.5,82,55.7'], ['28,17.9,80,58.3'], ['29,18.0,80,51.5'], ['30,18.0,80,51.0'], ['31,20.6,87,77.0']]
As you guys can see I also can't use float() on list one either, because the list is a whole string on its own. Is there a way I can split the lists by indexing so I get:
['1', '8.3', '70', '10.3'].....
Any help is welcome.
"line.split(',')" split the string with "," and returns list.
for string '1,8.3,70,10.3' it will return [1, 8.3, 70, 10.3]
You can split the strings by the commas if you want. You should probably do everything before you append them to List_one though.
res = [float(x) for x in line.split(" ")[0].split(",")]
List_one.append(res)
Does this work how you want it to? Sorry I'm not sure what format the input is in so I'm kind of guessing
You could say:
res = line.split(" ")
# map takes a function as the first arg and a list as the second
list_of_floats = list(map(lambda n: float(n), res.split(",")))
# then you can
List_one.append(list_of_floats)
Which will still give you a nested list because you are pushing a list during each iteration of for line in f:, but each list would at least be floats as you've specified.
If you wanted to just get one flat list of floats instead of doing the initial line.split(' ') you could use regex to split the line read from the csv:
import re # at the top of your file
res = re.split(r'[\s\,]', line)
list_of_floats = list(map(lambda n: float(n), res))
List_one.append(list_of_floats)
This might help:
l =[['1,8.3,70,10.3'], ['2,8.6,65,10.3'], ['3,8.8,63,10.2'], ['4,10.5,72,16.4']]
l2 =[]
for x in l:
a =x[0].split(",")
l2.append(a)
print(l2)
Enjoy!
I have a file with text with only 0's and 1's. No space between them. Example:
0101110
1110111
I would like to read a character at a time and place them as a single element in a list of integers.
My code:
intlist = []
with open('arq.txt', 'r') as handle:
for line in handle:
if not line.strip():
continue
values = map(int, line.split())
intlist.append(values)
print intlist
handle.close()
My result:
[[101110], [1110111]]
Like if I transform the 0101110 in intlist = [0,1,0,1,1,1,0,1,1,1,0,1,1,1]. (without '\n')
You just need two changes. The first is, when you're making values, you need to take each individual character of the line, instead of the entire line at once:
values = [int(x) for x in line.strip() if x]
Now, if you run this code on its own, you'll get [[1, 0, ...], [1, 1, ...]]. The issue is that if you call list.append with another list as an argument, you'll just add the list as an element. You're looking for the list.extend method instead:
intlist.extend(values)
Your final code would be:
intlist = []
with open('arq.txt', 'r') as handle:
for line in handle:
if not line.strip():
continue
values = [int(x) for x in line.strip() if x]
intlist.extend(values)
print intlist
If all you have is numbers and linefeeds, you can just read the file, remove the linefeeds, map the resulting string to integers, and turn that into a list:
with open('arq.txt') as handle:
intlist = list(map(int, handle.read().replace('\n', '')))
print intlist
Here's one way you can do it. You also don't need to use handle.close() the context manager handles closing the file for you.
intlist = []
with open('arq.txt', 'r') as handle:
for line in handle:
if not line.strip():
continue
intlist[:] += [int(char) for i in line.split() for char in i]
print(intlist)
Use strip() for delete \n and filter with bool for deleting empty strings:
with open('test.txt') as f:
lines = map(lambda x: x.strip(), filter(bool, f))
print [int(value) for number in lines for value in number]
One possibility:
intlist = []
with open('arq.txt', 'r') as handle:
for line in handle:
for ch in line.strip():
intlist.append (ch)
print intlist
I am a python newbie.
I want to read a text file which reads something like this
1345..
245..
..456
and store it in a list of lists of integers. I want to keep the numbers and replaces the periods by 0s.How do i do it?
EDIT:
Apologize for the ambiguous output spec
p.s I want the output to be a list of list
[ [1,3,4,5,0,0],
[2,4,5,0,0],
[0,0,4,5,6]]
with open('yourfile') as f:
lst = [ map(int,x.replace('.','0')) for x in f ]
Which is the same thing as the following nested list-comp:
lst = [ [int(val) for val in line.replace('.','0')] for line in f]
Here I used str.replace to change the '.' to '0' before converting to an integer.
with open(file) as f:
lis=[[int(y) for y in x.replace('.','0').strip()] for x in f]
Here's an answer in the form of classic for loops, which is easier for a newbie to understand:
a_list = []
l = []
with open('a') as f:
for line in f:
for c in line.rstrip('\n').replace('.', '0'):
l.append(int(c))
a_list.append(l)
#next line
l = []
print a_list
So like the title says im starting to learn some python and im having trouble picking up on this technique. What I need to accomplish is to read in some numbers and store them in a list. The text file looks like the following:
0 0 3 50
50 100 4 20
Basically these are coordinates and directions to be used for python's turtle to make shapes. I got that part down the only problem is getting them in a correct format. So what I can not figure out is how to get those numbers from the file into [ [0, 0, 3, 50], [50, 100, 4, 20] ]
A list, with each four coordinates being a list in that one big list.
Heres my attempt but it as I said I need some help - thank you.
polyShape=[]
infile = open(name,"r")
num = int(infile.readline(2))
while num != "":
polyShape.append(num)
num = int(infile.readline(2))
infile.close()
with open('data.txt') as f:
polyShape = []
for line in f:
line = line.split() # to deal with blank
if line: # lines (ie skip them)
line = [int(i) for i in line]
polyShape.append(line)
will give you
[[0, 0, 3, 50], [50, 100, 4, 20]]
This will work with a file that contains blank lines (or not).
Using the with construct will close the file for you automatically when you are done, or an exception is encountered.
Assuming there isn't actually a blank line in your input file:
with open(name, "r") as infile:
polyShape = [map(int, line.split()) for line in infile]
Explanation: map(int, line.split()) splits each line and converts each part to an int. The [X for Y in Z] construct is a list comprehension that in turn maps the map over all lines of the file and returns its results in a list.
If you find this too complicated for now, then the map(int, line.split()) is the main take-home message.
with open('data.txt') as f:
lis=[map(int,x.split()) for x in f if x.strip()] # if x.strip() to skip blank lines
#use list(map(int,x.split())) in case of python 3.x
this is how map() works:
>>> map(int,'1 2 3 4'.split())
[1, 2, 3, 4]
One-liner:
[ [int(x) for x in line.split(' ')] for line in open(name,'r').readlines() if line.strip()]
but the readlines part is probably not a great idea.
I'm quite sure that [int(x) for x in ... ] is faster than using map as in other suggested solutions.
Edit
Thanks to Blender : no need for .readlines, which is cool, so we just have :
[ map(int, line.split()) for line in open(name,'r') if line.strip()]
I also used map(int, ) because it's actually faster, and also you can use just line.split() instead of line.split(' ').
Iterating over the file would be the easiest way:
poly_shape = []
with open(name, 'r') as handle:
for line in handle:
if not line.strip():
continue # This skips blank lines
values = map(int, line.split())
poly_shape.append(values)
I do not recommend using append for a big array. It's 50 time slower than creating a zero array and assigning values to it.
import numpy
fname = "D:\Test.txt";
num_lines = sum(1 for line in open(fname));
array = numpy.zeros((num_lines,4));
k = 0;
with open(fname, "r") as ins:
for line in ins:
a =[int(i) for i in line.split(' ')];;
array[k,0:4] =a;
k = k+1;
print(array)