Is there an easy way in python of creating a list of substrings from a list of strings?
Example:
original list: ['abcd','efgh','ijkl','mnop']
list of substrings: ['bc','fg','jk','no']
I know this could be achieved with a simple loop but is there an easier way in python (Maybe a one-liner)?
Use slicing and list comprehension:
>>> lis = ['abcd','efgh','ijkl','mnop']
>>> [ x[1:3] for x in lis]
['bc', 'fg', 'jk', 'no']
Slicing:
>>> s = 'abcd'
>>> s[1:3] #return sub-string from 1 to 2th index (3 in not inclusive)
'bc'
With a mix of slicing and list comprehensions you can do it like this
listy = ['abcd','efgh','ijkl','mnop']
[item[1:3] for item in listy]
>> ['bc', 'fg', 'jk', 'no']
You can use a one-liner list-comprehension.
Using slicing, and relative positions, you can then trim the first and last character in each item.
>>> l = ['abcd','efgh','ijkl','mnop']
>>> [x[1:-1] for x in l]
['bc', 'fg', 'jk', 'no']
If you are doing this many times, consider using a function:
def trim(string, trim_left=1, trim_right=1):
return string[trim_left:-trim_right]
def trim_list(lst, trim_left=1, trim_right=1):
return [trim(x, trim_left, trim_right) for x in lst]
>>> trim_list(['abcd','efgh','ijkl','mnop'])
['bc', 'fg', 'jk', 'no']
If you want to do this in one line you could try this:
>>> map(lambda s: s[1:-1], ['abcd','efgh','ijkl','mnop'])
