Python | Encuentra la posición de un carácter en una string dada

Dada una string y un carácter, su tarea es encontrar la primera posición del carácter en la string. Estos tipos de problemas son una programación muy competitiva en la que necesita ubicar la posición del carácter en una string.
Analicemos algunos métodos para resolver el problema.
Método n.º 1: uso del método ingenuo 
 

# Python3 code to demonstrate
# to find the first position of the character
# in a given string
 
# Initializing string
ini_string = 'abcdef'
 
# Character to find
c = "b"
# printing initial string and character
print ("initial_string : ", ini_string, "\ncharacter_to_find : ", c)
 
# Using Naive Method
res = None
for i in range(0, len(ini_string)):
    if ini_string[i] == c:
        res = i + 1
        break
     
if res == None:
    print ("No such character available in string")
else:
    print ("Character {} is present at {}".format(c, str(res)))

initial_string :  abcdef 
character_to_find :  b
Character b is present at 2

  
Método n.º 2: usar find
Este método devuelve -1 en caso de que el carácter no esté presente. 
 

# Python3 code to demonstrate
# to find first position of character
# in a given string
 
# Initializing string
ini_string = 'abcdef'
ini_string2 = 'xyze'
 
# Character to find
c = "b"
# printing initial string and character
print ("initial_strings : ", ini_string, " ",
        ini_string2, "\ncharacter_to_find : ", c)
 
# Using find Method
res1 = ini_string.find(c)
res2 = ini_string2.find(c)
     
if res1 == -1:
    print ("No such character available in string {}".format(
                                                ini_string))
else:
    print ("Character {} in string {} is present at {}".format(
                                 c, ini_string, str(res1 + 1)))
     
if res2 == -1:
    print ("No such character available in string {}".format(
                                               ini_string2))
else:
    print ("Character {} in string {} is present at {}".format(
                                c, ini_string2, str(res2 + 1)))

Producción:

initial_strings :  abcdef   xyze  
character_to_find :  b
Character b in string abcdef is present at 2
No such character available in string xyze

  
Método n.º 3: uso de index()
Este método genera un error de valor en caso de que el carácter no esté presente 
 

# Python3 code to demonstrate
# to find first position of character
# in a given string
 
# Initializing string
ini_string1 = 'xyze'
 
# Character to find
c = "b"
# printing initial string and character
print ("initial_strings : ", ini_string1,
             "\ncharacter_to_find : ", c)
 
# Using index Method
try:
    res = ini_string1.index(c)
    print ("Character {} in string {} is present at {}".format(
                                  c, ini_string1, str(res + 1)))
except ValueError as e:
    print ("No such character available in string {}".format(ini_string1))

Producción:

initial_strings :  xyze  
character_to_find :  b
No such character available in string xyze