CODEWITHSUNDEEP
pythonlist
Samuel
Samuel

Reputation: 27

Read and print n number of lines of a python list

I want to print the first 10 lines of a list

I am new to python. This actually my first python project. I don't know how to go about it.

The list looks like this. How do we call such a list in python?

numbers = [[0.4437678, 0.4318693, 0.3873539, 0.03706345]]
          [[0.4437677, 0.4318692, 0.3873538, 0.03706344]]
          [[0.2260452, 0.2189278, 0.1944221, 0.01853172]]
          [[0.2260452, 0.2189278, 0.1944227, 0.01853173]]
          [[0.2260452, 0.2189278, 0.1944227, 0.01853173]]
          ...
          ...
          ...
          [[0.2260452, 0.2189278, 0.1944221, 0.01853172]]
          up to about 500 lines

I want to read and print the first 10 lines of this list

Upvotes: 0

Views: 1634

Answers (4)

Kermit
Kermit

Reputation: 5982

An example with a generator and no leading zero when slicing the list.

my_list = [1,2,3,4,5,6,7,8,9,10,11]

print(* (x for x in my_list[:10]), sep='\n' )

1
2
3
4
5
6
7
8
9
10

Here, I believe * is used to unpack the generator object.

Also, pandas uses the shorthand [:] syntax a lot so it will be good to get used to.

Upvotes: 1

Swadhikar
Swadhikar

Reputation: 2200

The most efficient way is to use list slicing which goes like input_list[0:10] where 0 is inclusive index and 10 is exclusive. So you would end up processing elements from 0 through 9.

for element in input_list[0:10]:
    # process with element
    ...

Upvotes: 1

Kalana
Kalana

Reputation: 6143

You don't have specify your dataset assign to which variable. If you use this

mydata = [[0.4437678, 0.4318693, 0.3873539, 0.03706345]]
          [[0.4437677, 0.4318692, 0.3873538, 0.03706344]]
          [[0.2260452, 0.2189278, 0.1944221, 0.01853172]]
          [[0.2260452, 0.2189278, 0.1944227, 0.01853173]]
          [[0.2260452, 0.2189278, 0.1944227, 0.01853173]]
          ...
          ...
          ...
          [[0.2260452, 0.2189278, 0.1944221, 0.01853172]]
          up to about 500 lines

use this code

mydata[0:10]

This will give you first 10 raws of your dataset

Upvotes: 1

MyNameIsCaleb
MyNameIsCaleb

Reputation: 4489

You have a nested list. See below for how to access using indices:

test = [['item1']]

print(test)
>> [['item1']]

print(test[0])
>> ['item1']

print(test[0][0])
>> 'item1'

You haven't given how your series of lists is stored, but you'll probably be able to cut off how many you want using slicing:

series[:10]

So if your series looked like this (a list of nested lists):

series = [[['item1']],
[['item2']],
[['item3']],
[['item4']],
[['item5']],
[['item6']],
[['item7']],
[['item8']],
[['item9']],
[['item10']],
[['item11']]]

And you wanted to grab the first 10, it would be:

series[:10]

If you want to unnest, you would need to access each maybe in a loop:

for i in range(0, 10):
    print(series[i][0][0])

To give you:

item1
item2
item3
item4
item5
item6
item7
item8
item9
item10

Upvotes: 3

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