Python - insert into list

Question

I get an array form a csv file and I get an list that looks like

my_list = ["Nov '15", '75', '49', '124', '62', '18', '80', '64.5', '', '', '', '', '', '', '', '']

And now I want to fill the spots where there is '' with an array of items that is that length, lets say the array I want to put in there is

new_array = [1,2,3,4,5,6,7,8]

here is what I am trying but it doesn't work.

i = 0
for item in new_array:
    index = 8+i
    print item
    my_list.insert(index, item)
    i += 0

It doesn't change anything my_list is just the same?

How can I change this?

Thanks

'' always start at index 8?

Andrés Pérez-Albela H.
– Andrés Pérez-Albela H.

2015-11-26 03:26:44 +00:00
Commented Nov 26, 2015 at 3:26 — Andrés Pérez-Albela H.
– Andrés Pérez-Albela H., Commented Nov 26, 2015 at 3:26

Óscar López · Accepted Answer · 2015-11-26 03:27:44Z

3

Try this:

i = 8
for item in new_array:
    my_list[i] = item # you want to replace the value
    i += 1            # you forgot to increment the variable

You weren't incrementing the variable i, and insert() moves the items to the right, it doesn't substitute them. Of course, a more idiomatic solution would be:

my_list = my_list[:8] + new_array

edited Nov 26, 2015 at 3:27

answered Nov 26, 2015 at 3:22

Óscar López

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W. Steve · Accepted Answer · 2015-11-26 03:23:44Z

0

my_list = ["Nov '15", '75', '49', '124', '62', '18', '80', '64.5', '', '', '', '', '', '', '', '']
new_array = [1,2,3,4,5,6,7,8]
i = 0
for item in new_array:
    index = 8+i
    print item
    my_list.remove('')
    my_list.insert(index, item)
    i += 1
print my_list

output:

1
2
3
4
5
6
7
8
["Nov '15", '75', '49', '124', '62', '18', '80', '64.5', 1, 2, 3, 4, 5, 6, 7, 8]

answered Nov 26, 2015 at 3:23

W. Steve

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Comments

Mikhail Gerasimov · Accepted Answer · 2015-11-26 03:32:12Z

0

Something like this:

new_iter = iter(new_array)
my_list = [i if i != '' else next(new_iter) for i in my_list]
print(my_list)

answered Nov 26, 2015 at 3:32

Mikhail Gerasimov

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Comments

Andrés Pérez-Albela H. · Accepted Answer · 2015-11-26 03:37:29Z

0

This code will work with '' (empty strings) starting at any index:

my_list = ["Nov '15", '75', '49', '124', '62', '18', '80', '64.5', '', '', '', '', '', '', '', '']

starts_at = my_list.index('')
amount_of_empty_strings = 0

for i, item in enumerate(my_list):
    if item.strip() == "":
        my_list[amount_of_empty_strings+starts_at] = amount_of_empty_strings+1
        amount_of_empty_strings+=1

print my_list

Output:

["Nov '15", '75', '49', '124', '62', '18', '80', '64.5', 1, 2, 3, 4, 5, 6, 7, 8]

answered Nov 26, 2015 at 3:37

Andrés Pérez-Albela H.

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Comments

ashishmohite · Accepted Answer · 2015-11-26 04:01:51Z

0

Using list comprehension

>>> new_array = [1,2,3,4,5,6,7,8]
>>> new_array.reverse()
>>> new_array
[8, 7, 6, 5, 4, 3, 2, 1]
>>> [new_array.pop()  if item is '' else item  for item in my_list]
["Nov '15", '75', '49', '124', '62', '18', '80', '64.5', 1, 2, 3, 4, 5, 6, 7, 8]

OR

>>> from collections import deque
>>> new_array = deque([1,2,3,4,5,6,7,8])
>>> [new_array.popleft()  if item is '' else item  for item in my_list]
["Nov '15", '75', '49', '124', '62', '18', '80', '64.5', 1, 2, 3, 4, 5, 6, 7, 8]

edited Nov 26, 2015 at 4:01

answered Nov 26, 2015 at 3:42

ashishmohite

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