Sometimes, while working with Python lists, we can have a problem in which we need to get the count of strings that start with particular substring. This can have an application in web development and general programming. Lets discuss certain ways in which this task can be performed.
Method #1 : Using loop + startswith()
The combination of above functions can be used to perform this task. In this, we run a loop for each string in list and employ startswith() to get the strings that start with particular prefix.
# Python3 code to demonstrate # Prefix frequency in List # using loop + startswith() # Initializing list test_list = ['gfgisbest', 'geeks', 'gfgfreak', 'gfgCS', 'Gcourses'] # printing original list print("The original list is : " + str(test_list)) # Initializing substring test_sub = 'gfg' # Prefix frequency in List # using loop + startswith() res = 0for ele in test_list: if ele.startswith(test_sub): res = res + 1 # printing result print ("Strings count with matching frequency : " + str(res)) |
The original list is : [‘gfgisbest’, ‘geeks’, ‘gfgfreak’, ‘gfgCS’, ‘Gcourses’]
Strings count with matching frequency : 3
Method #2 : Using sum() + startswith()
The combination of above functions can be used to perform this task. In this, we perform the task of counting using sum() and startswith(), is used to perform task of checking of prefix.
# Python3 code to demonstrate # Prefix frequency in List # using sum() + startswith() # Initializing list test_list = ['gfgisbest', 'geeks', 'gfgfreak', 'gfgCS', 'Gcourses'] # printing original list print("The original list is : " + str(test_list)) # Initializing substring test_sub = 'gfg' # Prefix frequency in List # using sum() + startswith() res = sum(sub.startswith(test_sub) for sub in test_list) # printing result print ("Strings count with matching frequency : " + str(res)) |
The original list is : [‘gfgisbest’, ‘geeks’, ‘gfgfreak’, ‘gfgCS’, ‘Gcourses’]
Strings count with matching frequency : 3
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