The following syntax can be used to iterate over a list of lists:
my_list = [['a', 'b', 'c'], ['d', 'e', 'f'], ['g', 'h', 'i']] for x in my_list: for y in x: print(y)
Example of iterating over a list of lists
Let’s suppose that you have a list of lists of colors.
You can then iterate over the list of lists using the syntax below:
colors_list = [['blue', 'green', 'yellow'], ['black', 'purple', 'orange'], ['red', 'white', 'brown'] ] for x in colors_list: for y in x: print(y)
Here is the result:
blue
green
yellow
black
purple
orange
red
white
brown
Let’s now add the string ‘_color‘ at the end of each item within the list of lists, and then save the results in a new flatten list called the new_colors_list:
colors_list = [['blue', 'green', 'yellow'], ['black', 'purple', 'orange'], ['red', 'white', 'brown'] ] new_colors_list = [] for x in colors_list: for y in x: new_colors_list.append(y + '_color') print(new_colors_list)
As you can see, the the string ‘_color’ was added at the end of each item in the final list:
['blue_color', 'green_color', 'yellow_color',
'black_color', 'purple_color', 'orange_color',
'red_color', 'white_color', 'brown_color']
Optionally, you can use a list comprehension to achieve the same results:
colors_list = [['blue', 'green', 'yellow'], ['black', 'purple', 'orange'], ['red', 'white', 'brown'] ] new_colors_list = [(y + '_color') for x in colors_list for y in x] print(new_colors_list)
The result:
['blue_color', 'green_color', 'yellow_color',
'black_color', 'purple_color', 'orange_color',
'red_color', 'white_color', 'brown_color']