[Baypiggies] string question

[Vikram K]

Given a string and some indices, how do i change upper characters
corresponding to some position(s) in the string to lower characters? I tried
and failed.

>>> x = 'EPSPVRYDNLSR'
>>> z = [2, 6]
>>> for i in z:
    print x[i]


S
Y
>>> for i in z:
    print x[i].lower()


s
y
>>> for i in z:
    x[i] = x[i].lower()


Traceback (most recent call last):
  File "<pyshell#14>", line 2, in <module>
    x[i] = x[i].lower()
TypeError: 'str' object does not support item assignment
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