a = 'hello world!!!'
print(a[0])
print(a[1])
print(a[-1])
print(a[-5])
print(a[1:4])
print(a[-5:-3])
print(a[:4])
print(a[-5:])

 
h
e
!
l
ell
ld
hell
ld!!!

a = 'hello world!!!'
print(a)

hello world!!!

a = 'hello' * 3
print(a)

hellohellohello

a = 'hello'
b = 'world!!!'
c = a + b
print(c)

helloworld!!!

a = 'hello'
b = 'world!!!'
c = ' '.join([a, b])
print(c)

hello world!!!

import re
a = 'abcdefghijk'
b = re.split('(..)',a)[1::2]
print(b)

['ab', 'cd', 'ef', 'gh', 'ij']

a = 'abcdefghijk'
b = [ a[i: i+2] for i in range(0, len(a), 2) ]
print(b)

['ab', 'cd', 'ef', 'gh', 'ij', 'k']

a = 'abcabcabcabcabcabcabc'
b = a.index('c')
print(b)

2

a = 'abcabcabcabcabcabcabc'
b = [ n for n, s in enumerate(a) if s == 'c' ]
print(b)

[2, 5, 8, 11, 14, 17, 20]

a = 'abcdddddefffg'
b = max( set(a), key=a.count )
print(b)

d

a = 'abcdefg'
b = a[::-1]
print(b)

gfedcba

a = 'a_b_c_d_e_f_g'
b = a[::2]
print(b)

abcdefg

a = '334'
b = int(a)
print(b, type(b))

334 <class 'int'>

a = '123abcABC'
b = [ ord(c) for c in a ]
print(b)

[49, 50, 51, 97, 98, 99, 65, 66, 67]

a = '123abcABC'
b = a.encode()
c = [c for c in b]
print(b)
print(c)

b'123abcABC'
[49, 50, 51, 97, 98, 99, 65, 66, 67]

a = '123xyzXYZ'
b = a.encode()
c = b.hex()
print(b, type(b))
print(c, type(c))

b'123xyzXYZ' <class 'bytes'>
31323378797a58595a <class 'str'>