Case conversion
Use .upper() and .lower() to normalise text for comparisons:
breed = "Beagle"
print(breed.upper()) # BEAGLE
nickname = "SparKy"
print(nickname.lower()) # sparky
response = input("Do you want water? ")
if response.lower() == "yes":
print("I'll get you a glass.")
else:
print("Alright, stay hydrated!")Counting characters
Use .count(substring) to count occurrences (case-sensitive unless you normalise first):
text = input("Type a sentence: ")
count_e = text.count("e")
print("The letter 'e' appears", count_e, "times.")Measuring string length
len(string) returns the number of characters—useful for validation:
fruit = input("Enter a fruit name: ")
print("The name has", len(fruit), "characters.")Checking start/end
Use .startswith() and .endswith() for pattern checks:
country = input("Enter a country: ")
if country.endswith("land"):
print("You've entered a country ending with 'land'.")
elif country.endswith("stan"):
print("You've entered a country ending with 'stan'.")
else:
print("Thanks for your entry.")Reversing text
Slice with a step of -1 to reverse:
user_text = input("Enter a sentence: ")
print("Reversed:", user_text[::-1])Splitting into words
.split() breaks a string into a list (default: spaces). Then analyse words:
sentence = input("Enter a sentence: ")
words = sentence.split()
print("Total words:", len(words))
s_count = 0
for word in words:
if word.lower().startswith("s"):
s_count += 1
print("Words starting with 's':", s_count)
Tips:
- Normalise with
.strip()to remove leading/trailing spaces. - For case-insensitive searches, compare on
text.lower(). - Use slicing:
text[a:b]for substrings; omit ends to go from start or to end.
Practice tasks
Task 1: Format a name
Ask for first name and surname; show SURNAME, first.
Show answer
first_name = input("Enter your first name: ").strip()
surname = input("Enter your surname: ").strip()
formatted = surname.upper() + ", " + first_name.lower()
print("Welcome", formatted)Task 2: Count the letter "a"
Count both uppercase and lowercase a in a sentence.
Show answer
sentence = input("Enter a sentence: ")
a_count = sentence.lower().count("a")
print("The letter 'a' appears", a_count, "times.")Task 3: Validate name length
Check if a name’s length is between 4 and 10 characters inclusive.
Show answer
name = input("Enter a name: ")
if 4 <= len(name) <= 10:
print("That name is just right!")
else:
print("The name must be between 4 and 10 characters.")Task 4: Middle character
Input a long word and print the middle character.
Show answer
word = input("Enter a long word: ")
mid = len(word) // 2
print("The middle character is:", word[mid])Task 5: Word counter
Show the total number of words and how many start with s.
Show answer
sentence = input("Enter a sentence: ")
word_list = sentence.split()
total = len(word_list)
s_words = sum(1 for w in word_list if w.lower().startswith("s"))
print("Total words:", total)
print("Words starting with 's':", s_words)