In this post we’ll see how to get a substring from a string in Python. Driven by habit most of the developers look for a method in the str class for getting a substring but in Python there is no such method. Getting a substring from a string is done through String slicing in Python.
Format of String slicing is as follows-
Stringname[start_position: end_position: increment_step]
start_position is the index from which the string slicing starts, start_position is included.
end_position is the index at which the string slicing ends, end_position is excluded.
increment_step indicates the step size. For example if step is given as 2 then every alternate character from start_position is accessed.
All of these parameters are optional, if start_position is not specified then the slicing starts from index 0. If end_position is not specified then the slicing ends at string_length – 1 (last index). If increment_step is not specified then increment step is 1 by default.
Getting substring through Python string slicing examples
1. A simple example where substring from index 2..3 is required.
s = "Test String" print(s[2: 4: 1])
st
Here slicing is done from index 2 (start_pos) to index 3 (end_pos-1). Step size is 1.
2. Access only the month part from a date in dd/mm/yyyy format. In this case you can use find method to specify the start and end positions for getting a substring.
s = "18/07/2019"
month = s[s.find("/")+1: s.rfind("/") : 1]
print('Month part of the date is-', month)
Month part of the date is- 07
That's all for this topic Getting Substring in Python String. If you have any doubt or any suggestions to make please drop a comment. Thanks!
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