I want to convert the first column of data from a text file into a list in python
data = open ('data.txt', 'r')
data.read()
provides
'12 45\n13 46\n14 47\n15 48\n16 49\n17 50\n18 51'
Any help, please.
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2 Answers
You can use str.split and a list comprehension here:
with open('data.txt') as f:
lis = [int(line.split()[0]) for line in f]
>>> lis
[12, 13, 14, 15, 16, 17, 18]
If the numbers to be strings:
>>> with open('abc') as f:
lis = [line.split()[0] for line in f]
>>> lis
['12', '13', '14', '15', '16', '17', '18']
Simplified version:
>>> with open('abc') as f: #Always use with statement for handling files
... lis = []
... for line in f: # for loop on file object returns one line at a time
... spl = line.split() # split the line at whitespaces, str.split returns a list
... lis.append(spl[0]) # append the first item to the output list, use int() get an integer
... print lis
...
['12', '13', '14', '15', '16', '17', '18']
help and example on str.split:
>>> strs = "a b c d ef gh i"
>>> strs.split()
['a', 'b', 'c', 'd', 'ef', 'gh', 'i']
>>> print str.split.__doc__
S.split([sep [,maxsplit]]) -> list of strings
Return a list of the words in the string S, using sep as the
delimiter string. If maxsplit is given, at most maxsplit
splits are done. If sep is not specified or is None, any
whitespace string is a separator and empty strings are removed
from the result.
answered Jun 11, 2013 at 8:22
Ashwini Chaudhary
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1 Comment
Ashwini Chaudhary
@lisa I've added some explanation.
import csv
with open ('data.txt', 'rb') as f:
print [row[0] for row in csv.reader(f, delimiter=' ')]
['12', '13', '14', '15', '16', '17', '18']
1 Comment
lisa
I want to get the list of integers (not of strings)