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Python String Practice Problems
Write a Python program to calculate the length of a string with a loop instead of len().
"sqatools"
8 True
text = "sqatools"count = 0for _ in text: count += 1print(count, count == len(text))8 True
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Write a Python program to find the longest and the shortest word in a string.
"Python makes string handling easy"
Longest: handling Shortest: easy
max / min with key=len.text = "Python makes string handling easy"words = text.split()print("Longest:", max(words, key=len))print("Shortest:", min(words, key=len))Longest: handling Shortest: easy
key=len compares words by their length; on a tie, the first such word wins.
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Write a Python program to test whether a letter is a vowel or a consonant.
"e", "K", "3"
e -> vowel K -> consonant 3 -> not a single letter
def kind(ch): if not ch.isalpha() or len(ch) != 1: return "not a single letter" return "vowel" if ch.lower() in "aeiou" else "consonant" for ch in ["e", "K", "3"]: print(ch, "->", kind(ch))e -> vowel K -> consonant 3 -> not a single letter
Digits, symbols and longer strings are rejected first.
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Write a Python program to count how many times a substring occurs in a string.
text = "the cat sat on the mat with the hat", sub = "the"
3 4
str.count().text = "the cat sat on the mat with the hat"print(text.count("the"))print(text.count("at"))3 4
count() counts non-overlapping occurrences.
Because matches do not overlap, "aaaa".count("aa") is 2, not 3.
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Write a Python program to reverse a string if its length is a multiple of 4; otherwise return it unchanged.
"Python", "sqatools"
Python -> Python sqatools -> slootaqs
len(text) % 4 == 0, then reverse with [::-1].for text in ["Python", "sqatools"]: result = text[::-1] if len(text) % 4 == 0 else text print(text, "->", result)Python -> Python sqatools -> slootaqs
“sqatools” has 8 characters, so it is reversed; “Python” has 6, so it is not.
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Write a Python program to make a string of 4 copies of the last two characters of a string (length must be at least 2).
"Python"
onononon
* 4.text = "Python"if len(text) >= 2: print(text[-2:] * 4)else: print("String must have at least 2 characters")onononon
text[-2:] is “on”; multiplying a string repeats it.
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Write a Python program that returns the length of the longest string in a list.
["python", "is", "readable", "fun"]
8 | 8 | readable
max() with len.words = ["python", "is", "readable", "fun"]longest = 0for w in words: if len(w) > longest: longest = len(w)print(longest, "|", max(len(w) for w in words), "|", max(words, key=len))8 | 8 | readable
Keep the biggest length seen so far.
max(len(w) for w in words) does the same in one line; max(words, key=len) returns the word itself.
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Write a Python program to build a string from the first 2 and the last 2 characters of a string. If the string is shorter than 2 characters, return an empty string.
"Sqatools", "Py", "S"
'Sqatools' -> 'Sqls' 'Py' -> 'PyPy' 'S' -> ''
def ends(text): if len(text) < 2: return "" return text[:2] + text[-2:] for t in ["Sqatools", "Py", "S"]: print(repr(t), "->", repr(ends(t)))'Sqatools' -> 'Sqls' 'Py' -> 'PyPy' 'S' -> ''
Strings shorter than 2 characters return an empty string, as the task asks.
text[:2] is the first two characters and text[-2:] the last two.
For “Py” the two slices overlap, so the result is “PyPy”.
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