Python | Checking if starting digits are similar in list

Sometimes we may face a problem in which we need to find for a list if it contains numbers with the same digits. This particular utility has an application in day-day programming. Let’s discuss certain ways in which this task can be achieved.

Method #1 : Using list comprehension + map()
We can approach this problem by converting the elements to the strings and then testing the starting element of string and if they are equal we can return true and then convert to set and test for size of result to be one. The conversion is done by map, set function converts to set and list comprehension checks for first element of string.

filter_none

edit
close

play_arrow

link
brightness_4
code

# Python3 code to demonstrate
# checking for first digit in elements
# using list comprehension + map()
  
# initializing list 
test_list = [45, 4, 428829, 432]
  
# printing original list
print("The original list : " + str(test_list))
  
# using list comprehension + map()
# checking for first digit in elements
res = len(set(sub[0] for sub in  map(str, test_list))) == 1
  
# print result
print("Does each element start with same digit ? " + str(res))

chevron_right


Output :

The original list : [45, 4, 428829, 432]
Does each element start with same digit ? True

 

Method #2 : Using all() + list comprehension
This is yet another approach in which this problem can be solved. In this we use all function to check for all elements and return a Boolean result and list comprehension does the part of conversion of string by str function and checking for all elements with the first digit of first element.

filter_none

edit
close

play_arrow

link
brightness_4
code

# Python3 code to demonstrate
# checking for first digit in elements
# using all() + list comprehension
  
# initializing list 
test_list = [45, 4, 428829, 432]
  
# printing original list
print("The original list : " + str(test_list))
  
# using all() + list comprehension
# checking for first digit in elements
res = all(str(i)[0] == str(test_list[0])[0] for i in test_list)
  
# print result
print("Does each element start with same digit ? " + str(res))

chevron_right


Output :

The original list : [45, 4, 428829, 432]
Does each element start with same digit ? True


My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.




Article Tags :

Be the First to upvote.


Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.