根据字符串中的第一个字符，查找字符串列表中第一个元素的出现位置

Question

I am new to python. I am trying to get the 1st number in a list of strings that are numbers in a series, that start with a common number.

ex:

x = ['512','345','321','345','674','132','231','145','214','576']

my expected output:

result = ['512','345','674','132','231']

ie say for example in all numbers starting with 1 in list, I should get the 1st number likewise for all other numbers.

I could use for loop twice to get it. but i want to know is there any better way of doing it.

NOTE: the list is a list of strings which are numbers given was just an example.

Answer 1

You can use a generator function to do this. In the function you just iterate your initial list and for each element check if there is another element that starts with the same character already exists in a set of string. If no match found, just yield that element.

>>> def get_num(lst):
...     found = set()
...     for element in lst:
...         if not any(item.startswith(element[0]) for item in found):
...             found.add(element)
...             yield element
... 
>>> x = ['512','345','321','345','674','132','231','145','214','576']
>>> list(get_num(x))
['512', '345', '674', '132', '231']