How can I find where a string is in a list?

Question

I want to set a variable to a certain value in a list. I need to find where the specific string is in the list without knowing what the contents of the list will be. For instance:

list = ["a", "b", "c"]
valueIWantToFind = "b"

# code that finds where value is


variable = list.1

I thought of doing a for loop, but I don't know how to get the current value of the list to compare it to the value I want to find.

Some thing like this:

for x in list:
 if(valueIWantToFind == currentValueOfList):
   variable = currentValueOfList
 else:
   continue

`if(valueIWantToFind in currentValueOfList):variable==currentValueOfList` No need to use for loop. — codester_09, Jun 07 '22 at 15:47
What do you think the `where` will give you? Do you just want to know whether the value is in the list or do you want its index? — quamrana, Jun 07 '22 at 15:48

score 0 · Answer 1 · answered Jun 07 '22 at 15:52

I would use a list comprehension with an if condition

my_list = ["a", "b", "c"]

value_i_want_to_find = "b"

idx_list = [i for i, el in enumerate(my_list) if el == value_i_want_to_find]

You'll have a list of indices where the element equals value_i_want_to_find.

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EDIT: Already answered here Finding the index of an item in a list

score 0 · Accepted Answer · answered Jun 07 '22 at 16:02

"I need to find where the specific string is in the list without knowing what the contents of the list will be".

For this you would use the index() function of a list but also take into account that if what you're looking for doesn't exist you'll get an exception.

For example:

list_ = ['a', 'b', 'c']
try:
  idx = list_.index('b')
  print(f'Found at index {idx}')
  idx = list_.index('z')
  print(f'Found at index {idx}') # this won't happen
except ValueError:
  print('Not found') # this will happen when we search for 'z'

Output:

Found at index 1
Not found

How can I find where a string is in a list?

2 Answers2