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The Driven Noise
The Driven Noise

Reputation: 43

Making lists from multiple lines in a text file (Python)

I am trying to turn a text file into multiple lists but I am unsure how, say for example the text file is: 

Bob 16 Green
Sam 19 Blue
Sally 18 Brown

I then want to make three lists,

[Bob, Sam, Sally] , [16, 19, 18], [Green, Blue, Brown]

thanks

Upvotes: 1

Views: 2117

Answers (4)

user3905264
user3905264

Reputation: 7

lines.txt has the text contents:

*

Bob 16 Green
Sam 19 Blue
Sally 18 Brown

*

Python code:

with open ("lines.txt", "r") as myfile:
  data = myfile.readlines()
  for line in data:
    list = [word for word in line.split()]
    print list

Upvotes: -1

vencaslac
vencaslac

Reputation: 2884

the code below does what you want:

names = []
ages = []
fav_color = []

flist=open('myfile.txt','r').read().split('\n')
for line in flist:
    names.append(line.split(' ')[0])
    ages.append(line.split(' ')[1])
    fav_color.append(line.split(' ')[2])

print(names)
print(ages)
print(fav_color)

Upvotes: -1

Jean-François Fabre
Jean-François Fabre

Reputation: 140316

Keeping tokens as strings (not converting integers or anything), using a generator comprehension:

Iterate on the file/text lines, split your words and zip the word lists together: that will "transpose" the lists the way you want:

f = """Bob 16 Green
Sam 19 Blue
Sally 18 Brown""".splitlines()

print (list(zip(*(line.split() for line in f))))

result (as a list of tuples):

[('Bob', 'Sam', 'Sally'), ('16', '19', '18'), ('Green', 'Blue', 'Brown')]

* unpacks the outer generator comprehension as arguments of zip. results of split are processed by zip.

Even simpler using map which avoids the generator expression since we have split handy, (str.split(x) is the functional notation for x.split()) (should even be slightly faster):

print (list(zip(*map(str.split,f))))

Note that my example is standalone, but you can replace f by a file handle all right.

Upvotes: 4

Hans
Hans

Reputation: 2502

A simple oneliner, assuming you load the file as a string:

list(zip(*[line.split(' ') for line in filecontent.split('\n')]))

I first split it at all the new lines, each of those at all of the spaces, and then flip it (zip-operator)

Upvotes: 1

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