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MIT OPEN COURSEWARE CS 6.0001 PYTHON LECTURE 3
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Strings
function len:length of string
s = “abc” len s = 3
indexing:in Python, index at position 0.
using negative numbers to index
-1 == the last character in the string.
so on.
get a substring_slice into a string
slice strings using [start: stop:step]
step = 1 by default
can also omit numbers and leave just colons
EX:
s = “abcdefgh”
01234567
s[3:6] is same as s[3:6:1], evaluates to “def”
s[3:6:2] “df”
s[::] == s
s[::-1] is same as s[-1:[(len(s)+1) : -1], which turns the string around
s[4:1:-2] == “ec”
strings are “immutable”-cannot be modified.
s = “hello”
s[0] = y -> error
s = ‘y’ + s[1:len(s)] ->allowed, bound to new object
for loops
for var in range(4,6)->var = 4,5
EX: