How do I append the index of a string to a list using extend() in python?

March 4, 2023

I’m trying to look through a long string to find instances of a substring, then I want to create a list that has the index of each substring found and the substring found. But instead of the index in a readable form, I’m getting a reference to the object, such as [<built-in method index of str object at 0x000001687B01E930>, 'b']. I’d rather have [123, 'b'].

Here’s the code I’ve tried:

test_string = "abcdefg"
look_for = ["b","f"]
result = []

for each in test_string:
    if each in look_for:
        result.extend([each.index, each])
        
print(result)

I know I could do this with a list comprehension, but I plan to add a bunch of other code to this for later and am only asking about the index issue here.

I’ve tried str(each.index) and print(str(result))

But that doesn’t help. What am I missing?

>Solution :

Here are 2 ways you can achieve it, either using .index() or enumerate()

test_string = "abcdefg"
look_for = ["b","f"]
result = []

for i, each in enumerate(test_string):
    if each in look_for:
        result.append((i, each))
        
print(result)

result =  []

for i in look_for:
    try:
        result.append((i, test_string.index(i)))
    except:
        pass
print(result)