CODEWITHSUNDEEP
pythonlistarr
William Merritt
William Merritt

Reputation: 439

How to store multi-line input into a list (python)

How would you store a multi-line input into an list?

For example: 

3
2 1
1 1 0
2 1 1
4 3 0 1 2
2 
1 2
1 3

How would I take that input and store it as a list like so: 

examList = [
      [3],
      [2,1],
      [1,1,0], 
      [2,1,1], 
      [4,3,0,1,2], 
      [2],
      [1,2],
      [1,3]
]

How do you identify the end user input if there any no specific indicators?

Upvotes: 0

Views: 7844

Answers (3)

liofpi
liofpi

Reputation: 21

You can use sys.stdin.readlines().

For example, start with

import sys
user_input = sys.stdin.readlines()

at this point, the value of user_input should be

['3\n', '2 1\n', '1 1 0\n', '2 1 1\n', '4 3 0 1 2\n', '2\n', '1 2\n', '1 3']

then, you should be able to get your desired output by performing the following processing

examList = []

for input_string in user_input:
   examList.append([int(value) for value in input_string.split()])

What we are doing here is iterating through user_input. For each input_string, we split() the words, convert them to int and put them back into a new list. Then, the new list will be added into examList.

Upvotes: 2

Mike Peder
Mike Peder

Reputation: 738

Here's an effective one-liner:

>>> inp = '''3
2 1
1 1 0
2 1 1
4 3 0 1 2
2 
1 2
1 3'''
>>> [i.split() for i in inp.split('\n')]

[['3'], ['2', '1'], ['1', '1', '0'], ['2', '1', '1'], ['4', '3', '0', '1', '2'], ['2'], ['1', '2'], ['1', '3']]

Upvotes: 1

Joe Iddon
Joe Iddon

Reputation: 20424

Keep calling the input() function until the line it reads in is empty. The use the .split method (no args = space as deliminator). Use a list-comp to convert each string to an int and append this to your examList.

Here's the code:

examList = []
i = input()
while i != '':
    examList.append([int(s) for s in i.split()])
    i = input()

And with your input, examList is:

[[3], [2, 1], [1, 1, 0], [2, 1, 1], [4, 3, 0, 1, 2], [2], [1, 2], [1, 3]]

The above method is for Python3 which allows you to call input() and enter nothing (which is why we use this as a signal to check that we are done - i != '').

However, from the docs, we see that, in Python2, an empty entry to input() throws an EOF error. To get around this, I guess we could just make it so that the multi-line input is ended when the string such as: END is entered. This means that you must stop the entry with a line saying 'END':

examList = []
i = raw_input()
while i != 'END':
    examList.append([int(s) for s in i.split()])
    i = raw_input()

Note that I've used raw_input as to not perform type conversion.

which works the same as above.

Upvotes: 2

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