How to get char from string by index?

Lets say I have a string that consists of x unknown chars. How could I get char nr. 13 or char nr. x-14?

Answers:

Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

Method 1

First make sure the required number is a valid index for the string from beginning or end , then you can simply use array subscript notation.
use len(s) to get string length

>>> s = "python"
>>> s[3]
'h'
>>> s[6]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IndexError: string index out of range
>>> s[0]
'p'
>>> s[-1]
'n'
>>> s[-6]
'p'
>>> s[-7]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IndexError: string index out of range
>>>

Method 2

In [1]: x = "anmxcjkwnekmjkldm!^%@(*)#<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="8ad5a1cabdb2b3b9bfbabbbebdbbb8e0e1f9eeecf9">[email protected]</a>"
In [2]: len(x)
Out[2]: 45

Now, For positive index ranges for x is from 0 to 44 (i.e. length – 1)

In [3]: x[0]
Out[3]: 'a'
In [4]: x[45]
---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)

/home/<ipython console> in <module>()

IndexError: string index out of range

In [5]: x[44]
Out[5]: 's'

For Negative index, index ranges from -1 to -45

In [6]: x[-1]
Out[6]: 's'
In [7]: x[-45]
Out[7]: 'a

For negative index, negative [length -1] i.e. the last valid value of positive index will give second list element as the list is read in reverse order,

In [8]: x[-44]
Out[8]: 'n'

Other, index’s examples,

In [9]: x[1]
Out[9]: 'n'
In [10]: x[-9]
Out[10]: '7'

Method 3

Previous answers cover about ASCII character at a certain index.

It is a little bit troublesome to get a Unicode character at a certain index in Python 2.

E.g., with s = '한국中国にっぽん' which is <type 'str'>,

__getitem__, e.g., s[i] , does not lead you to where you desire. It will spit out semething like �. (Many Unicode characters are more than 1 byte but __getitem__ in Python 2 is incremented by 1 byte.)

In this Python 2 case, you can solve the problem by decoding:

s = '한국中国にっぽん'
s = s.decode('utf-8')
for i in range(len(s)):
    print s[i]

Method 4

Python.org has an excellent section on strings here. Scroll down to where it says “slice notation”.

Method 5

Another recommended exersice for understanding lists and indexes:

L = ['a', 'b', 'c']
for index, item in enumerate(L):
    print index + 'n' + item

0
a
1
b
2
c

Method 6

This should further clarify the points:

a = int(raw_input('Enter the index'))
str1 = 'Example'
leng = len(str1)
if (a < (len-1)) and (a > (-len)):
    print str1[a]
else:
    print('Index overflow')

Input 3
Output m

Input -3
Output p

Method 7

I think this is more clear than describing it in words

s = 'python'
print(len(s))
6
print(s[5])
'n'
print(s[len(s) - 1])
'n'
print(s[-1])
'n'

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0