# Nested for loops to access images#

We can access the color information of certain columns of images in a similar way. We still have the 3X4 image saved as a 2D list `our_image`.

The RGB values of each pixel is as follows:

```(0,0,0)   (0,80,0)   (0,160,0)   (0,240,0)
(120,0,0) (120,80,0) (120,160,0) (120,240,0)
(240,0,0) (240,80,0) (240,160,0) (240,240,0)
```

Using tricks we’ve learned so far, we can output each column by copy/pasting code:

```for column in range(4):
print(our_image[1][column])

for column in range(4):
print(our_image[2][column])
```

```(120,0,0)
(120,80,0)
(120,160,0)
(120,240,0)
(240,0,0)
(240,80,0)
(240,160,0)
(240,240,0)
```

as we wanted. However, nested `for` loops can generate the same result with more concise code as follows:

```for row in range(1,3):
for column in range(4):
print(our_image[row][column])
```

Here are the details of how the nested `for` loops printed the desired result.

• `row` is `1` at the initial iteration of the outer `for` loop
• `column` is `0` at the initial iteration of the inner `for` loop

• `our_image[1][0]` is printed

• `column` is `1` at the next iteration of the inner `for` loop

• `our_image[1][1]` is printed

• `column` is `2` at the next iteration of the inner `for` loop

• `our_image[1][2]` is printed

• `column` is `3` at the next iteration of the inner `for` loop

• `our_image[1][3]` is printed

• `row` is `2` at the next iteration of the outer `for` loop
• `column` is `0` at the initial iteration of the inner `for` loop

• `our_image[2][0]` is printed

• `column` is `1` at the next iteration of the inner `for` loop

• `our_image[2][1]` is printed

• `column` is `2` at the next iteration of the inner `for` loop

• `our_image[2][2]` is printed

• `column` is `3` at the next iteration of the inner `for` loop

• `our_image[2][3]` is printed

Similarly, we can print the information of the entire image!

```for row in range(3):
for column in range(4):
print(our_image[row][column])
```

Here is the output.

```(0,0,0)
(0,80,0)
(0,160,0)
(0,240,0)
(120,0,0)
(120,80,0)
(120,160,0)
(120,240,0)
(240,0,0)
(240,80,0)
(240,160,0)
(240,240,0)
```

You can be assured that the correct information is printed according to the RGB table of the image above.