CODEWITHSUNDEEP
pythonpython-2.7
user2242044
user2242044

Reputation: 9243

Python looping through a list getting list indices error

I have an list and would like to loop through each row and print the value from column 1. I am getting the error message TypeError: list indices must be integers, not list What am I missing here?

test = [[1,2,4],[3,4,3]]

for currentrow in test:
     print test[currentrow][1]

Upvotes: 0

Views: 101

Answers (4)

user3885927
user3885927

Reputation: 3503

If you are trying to access second element in each of the arrays in the test this what you would do:

test = [[1,2,4],[3,4,3]]

for currentrow in test:
    print currentrow[1]

Upvotes: 1

Dan Loewenherz
Dan Loewenherz

Reputation: 11253

When you use a for loop in Python, the variable currentrow will be assigned the actual object in the list, not the index. So, what you want is the following:

test = [[1,2,4],[3,4,3]]

for currentrow in test:
     print currentrow[1]

A benefit of this approach is that it's a bit easier to read as well.

If you'd like the index to be available in the loop body, you can use enumerate. Here's an example:

test = [[1,2,4],[3,4,3]]

for i, currentrow in enumerate(test):
    print "Row {}: {}".format(i, currentrow[1])

Upvotes: 1

Zhouster
Zhouster

Reputation: 756

The issue with your code here is that when you loop through your test list, each entry is a list of its own. As such, you're trying to use that entry as an index, which is not possible. Try something like this:

for i in range(len(test)):
    print test[i][1]

Upvotes: 0

Hamatti
Hamatti

Reputation: 1220

In your example, currentrow will be a list.

So what you want to do is

test = [[1,2,4],[3,4,3]]

for currentrow in test:
    print currentrow[1]

will print

2
4

Upvotes: 2

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