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Python String Practice Problems
Write a Python program to remove all characters except a given one.
"Sqatools python", keep "S"
S
text = "Sqatools python"keep = "S"print("".join(ch for ch in text if ch == keep))S
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Write a Python program to build a string from the characters that appear in only one of two strings.
"abcdefg", "xyzabcd"
efgxyz
s1, s2 = "abcdefg", "xyzabcd"result = [ch for ch in s1 if ch not in s2] + [ch for ch in s2 if ch not in s1]print("".join(result))efgxyz
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Write a Python program to build a string of the characters that occur more than once.
"aabbcceffgh"
abcf
from collections import Countertext = "aabbcceffgh"counts = Counter(text)print("".join(ch for ch in counts if counts[ch] > 1))abcf
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Write a Python program to collapse consecutive duplicate characters into one.
"xxxxyy"
xyx
text = "xxxxyyxx"result = ""for ch in text: if not result or ch != result[-1]: result += chprint(result)xyx
not result handles the first character.
Only consecutive repeats are removed, so “xxxxyyxx” becomes “xyx”.
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Write a Python program to find the longest run of consecutive 0s in a binary string.
"10001100000111"
5
binary = "10001100000111"print(max(len(run) for run in binary.split("1")))5
Splitting on “1” leaves only the runs of zeros.
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Write a Python program to remove leading zeros from each part of an IP address.
"289.03.02.054"
289.3.2.54
ip = "289.03.02.054"print(".".join(str(int(part)) for part in ip.split(".")))289.3.2.54
int("054") is 54, which drops the zeros; int("0") stays 0.
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Write a Python program to add up the digits in a string.
"12sqatools78"
18
int(ch) for each digit character.print(sum(int(ch) for ch in "12sqatools78" if ch.isdigit()))18
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Write a Python program to capitalise the first and last letters of each word.
"this is my first program"
ThiS IS MY FirsT PrograM
def cap_ends(w): if len(w) == 1: return w.upper() return w[0].upper() + w[1:-1] + w[-1].upper() print(" ".join(cap_ends(w) for w in "this is my first program".split()))ThiS IS MY FirsT PrograM
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Write a Python program to remove all spaces from a string.
"python at sqatools"
pythonatsqatools
replace(" ", "").print("python at sqatools".replace(" ", ""))pythonatsqatools
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Write a Python program to find the second most repeated word.
"ab bc ac ab bd ac nk hj ac"
('ab', 2)Counter.most_common() returns words sorted by count.from collections import Counterprint(Counter("ab bc ac ab bd ac nk hj ac".split()).most_common(2)[1])('ab', 2)most_common(2) gives the top two pairs; index 1 is the second.
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