Are these Strings notes free?

Yes. The full 4-page Strings sheet is free inside CapCompass, which runs in your browser with no account needed.

What does the Strings revision sheet cover?

A string is a sequence, Indexing and slicing, Indexing and slicing s = 'PYTHON', Strings are immutable, Common string methods, split() and join(), two halves of the same idea, split and join, worked, 'a,b,c'.split(','), '-'.join(['a', 'b', 'c']), ' hi '.strip(), 'cat'.find('t'), 'cat'.find('z').

Is this for Class 11 CBSE Computer Science?

It is written from the NCERT syllabus, so it serves CBSE and any board that follows NCERT for Computer Science.

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Strings — Class 11 CBSE Computer Science revision notes

A 4-page visual revision sheet for Strings, written for Class 11 CBSE Computer Science. Formulas, diagrams and the traps that cost marks, laid out to be read the night before rather than the term before. Free, and it opens inside CapCompass.

Strings revision notes, page 1 of 4 — A preview of page 1 — all 4 pages open full size in the app.

Strings in one look

text as a sequence of characters, indexed, sliced, and never changed in place

A string is a sequence

a string is an ordered sequence of characters, written in single or double quotes
every character has a position, called its index, counted from the left starting at 0
negative indices count from the right instead, starting at -1 for the last character
len(s) reports how many characters a string holds

Indexing and slicing

s[i] gives the single character sitting at index i
s[start:stop] gives the slice from start up to, but not including, stop
a missing start defaults to 0, a missing stop defaults to the end of the string
s[start:stop:step] adds a step, s[::-1] with no start or stop and a step of -1 reverses the whole string

Indexing and slicing s = 'PYTHON'

Q. s = 'PYTHON', find s[0], s[-1], s[2:5], s[:3], s[::-1]

s[0] is the character at index 0, that's P
s[-1] is the last character, counting from the right, that's N
s[2:5] runs from index 2 up to but not including index 5, that's THO
s[:3] has no start, so it begins at 0 and stops before index 3, that's PYT
s[::-1] has no start or stop and a step of -1, walking the whole string backward, that's NOHTYP

Answer: P, N, THO, PYT, NOHTYP

Strings are immutable

a string can never be changed in place, s[0] = 'Z' raises a TypeError, there is no way around it
every string method that looks like it changes a string actually builds and returns a BRAND NEW string, leaving the original untouched
s = s.upper() looks like a change, but it's really s being rebound to a new string, the old one is simply discarded

Page 1 of 4. The full sheet, all 4 pages, opens free in the app.

What this Strings sheet covers

A string is a sequence
Indexing and slicing
Indexing and slicing s = 'PYTHON'
Strings are immutable
Common string methods
split() and join(), two halves of the same idea
split and join, worked
'a,b,c'.split(',')
'-'.join(['a', 'b', 'c'])
' hi '.strip()
'cat'.find('t')
'cat'.find('z')
String operators
Traversing a string
format() and f-strings
Terms that show up as one-liners
Traps that cost marks
Tricks that save time

Open the full Strings sheet →Free, works offline, no account needed. All 4 pages, plus a study plan built around your own exam dates.

How CapCompass uses this sheet

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