# How to add an integer to each element in a list?

If I have list=[1,2,3] and I want to add 1 to each element to get the output [2,3,4], how would I do that?

I assume I would use a for loop but not sure exactly how.

```new_list = [x+1 for x in my_list]
```

```>>> mylist = [1,2,3]
>>> [x+1 for x in mylist]
[2, 3, 4]
>>>
```

The other answers on list comprehension are probably the best bet for simple addition, but if you have a more complex function that you needed to apply to all the elements then map may be a good fit.

In your example it would be:

```>>> map(lambda x:x+1, [1,2,3])
[2,3,4]
```

if you want to use numpy there is another method as follows

```import numpy as np
list1 = [1,2,3]
list1 = list(np.asarray(list1) + 1)
```

```>>> [x.__add__(1) for x in [1, 3, 5]]
3: [2, 4, 6]
```

My intention here is to expose if the item in the list is an integer it supports various built-in functions.

Firstly don't use the word 'list' for your variable. It shadows the keyword list.

The best way is to do it in place using splicing, note the [:] denotes a splice:

```>>> _list=[1,2,3]
>>> _list[:]=[i+1 for i in _list]
>>> _list
[2, 3, 4]
```

Python 2+:

```>>> mylist = [1,2,3]
>>> map(lambda x: x + 1, mylist)
[2, 3, 4]
```

Python 3+:

```>>> mylist = [1,2,3]
>>> list(map(lambda x: x + 1, mylist))
[2, 3, 4]
```

```list = [1,2,3,4,5]

for index in range(5):
list[index] = list[index] +1

print(list)
```

Came across a not so efficient, but unique way of doing it. So sharing it across.And yes it requires extra space for another list.

```test_list1 = [4, 5, 6, 2, 10]
test_list2 =  * len(test_list1)

print(test_list1)
print(test_list2)
print(res_list)

#### Output ####
[4, 5, 6, 2, 10]
[1, 1, 1, 1, 1]
[5, 6, 7, 3, 11]
```