打印值不带双方括号python

Question

I'm trying to print a value without the double square brackets in python. Say I have

a = [[2]]

and I want to print the value into a textfile or whatnot. With

print(a)

I of course get

[[2]]

I tried

 print(np.asarray(a))
 print(str(a))
 print("" . join(str(a)))

all these commands return the same as above. How can I print the value without brackets?

Answer 1

using a[0][0], for example if a = [1,[2,3]]

a[1][1]

this gives you 3

Answer 2

[[2]] is a list containing a list containing the number 2.

To get the first element from a list, use a[0] .

To get the first element from a list and then the first element of that, use a[0][0] .

Answer 3

Although the answer is given in the comments below your question, this will just give you some idea on indexing. What you have is an integer value as a sublist within the list.

a = [[2]]

If you print its length and type

print (len(a), type(a))

you get

1 <class 'list'>

which means your a is a list with length 1. Since in python, indexing starts from 0 , the content of list a is accessed as a[0] . But now repeating the above step again,

print (len(a[0]), type(a[0]))

yields

1 <class 'list'>

which means the sublist a[0] is itself a list of length 1 and the content of this sublist a[0] can be accessed using the index 0 . This means 0 index of a[0] as a[0][0] . This can go on forever depending on the number of sublists. But eventually the integer inside will result in TypeError because integer has no length.

print (len(a[0][0]))

yields

TypeError: object of type 'int' has no len()

Hope you understood the gist behind all this sublist and indexing.