python how to run loop and append item in list until match with len of old list?-CodePudding

I am new in python. I have a list like this:

new_list = []
list1 = ['a','b','c']

I want to run loop and append item in my new_list by matching len of list1.
so my expected result will be somethings like this:

new_list = [1,2,3]

if my list1 = ['a','b'] then new_list = [1,2]

CodePudding user response：

Using range() and casting to a list:

>>> list1 = ['a','b','c']
>>> new_list = list(range(1, len(list1) 1))
>>> new_list
[1, 2, 3]

CodePudding user response：

thats how you can do it.

for x in range(1,len(list1) 1):
    new_list.append(x)
    
print(new_list)

CodePudding user response：

Using Python's list comprehension, you are able to do this with 2 lines of code.

list1 = ['a','b','c']
new_list = [i for i in range(1, len(list1) 1)]

CodePudding user response：

Another option is to use enumerate:

list1 = ['a','b','c']
output = [i for i, _ in enumerate(list1, start=1)]
print(output) # [1, 2, 3]