Merge branch 'master' of https://github.com/JustDoPython/python-100-day

Author: chengxianhuan

.DS_Store

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+import itertools
+x = itertools.chain("abc", "xyz")
+print(list(x))

README.md

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+import itertools
+print(list(itertools.combinations("abc", r=2)))

day-039/.DS_Store

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+import itertools
+print(list(itertools.combinations_with_replacement("abc", r=2)))

day-039/itertools-chain-demo.py

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+import itertools
+data = [81, 82, 84, 76, 64, 78]
+tf = [1,1,0,1,1,0]
+print(list(itertools.compress(data, tf)))

day-039/itertools-combinations-demo.py

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+import itertools
+x = itertools.count(1,2)
+for k in x:
+	print(k, end=", ")

day-039/itertools-combinations_with_replacement-demo.py

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+import itertools
+x = itertools.cycle("XYZ")
+for k in x:
+	print(k, end = ", ")

day-039/itertools-compress-demo.py

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+import itertools
+x = itertools.dropwhile(lambda x: x < 5, [1,3,5,7,4,2,1])
+print(list(x))

day-039/itertools-count-demo.py

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+import itertools
+x = itertools.filterfalse(lambda x: x < 5, [1,3,5,7,4,2,1])
+print(list(x))

day-039/itertools-cycle-demo.py

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+import itertools
+def sortBy(score):
+	if score > 80:
+		return "A"
+	elif score >= 60:
+		return "B"
+	else:
+		return "C"
+
+scores = [81, 82, 84, 76, 64, 78, 59, 44, 55, 89]
+#scores = sorted(scores, key=sortBy) # 将此行代码注释打开即可得到合理的结果
+for m, n in itertools.groupby(scores, key=sortBy):
+	print(m, list(n))

day-039/itertools-dropwhile-demo.py

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+import itertools
+print(list(itertools.islice('123456789', 2)))
+print(list(itertools.islice('123456789', 2, 4)))
+print(list(itertools.islice('123456789', 2, None)))
+print(list(itertools.islice('123456789', 0, None, 2)))

day-039/itertools-filterfalse-demo.py

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+import itertools
+print(list(itertools.permutations("aba", r=2)))

day-039/itertools-groupby-demo.py

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+import itertools
+print(list(itertools.product("ab", "12")))
+print(list(itertools.product("ab", "ab")))
+print(list(itertools.product("ab", repeat=2)))

day-039/itertools-islice-demo.py

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+import itertools
+#x = itertools.repeat("XYZ")
+x = itertools.repeat("XYZ", 3)
+for k in x:
+	print(k, end = ", ")

day-039/itertools-permutations-demo.py

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+import itertools
+print(list(itertools.starmap(pow,[(2,10), (3,3)])))

day-039/itertools-product-demo.py

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+import itertools
+x = itertools.takewhile(lambda x: x < 5, [1,3,5,7,4,2,1])
+print(list(x))

day-039/itertools-repeat-demo.py

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+import statistics
+
+example_list = [1,2,3,4,5,6]
+
+x = statistics.mean(example_list)
+print(x)
+
+x = statistics.harmonic_mean(example_list)
+print(x)
+print(1/sum([1/1,1/2,1/3,1/4,1/5,1/6])*6)
+
+x = statistics.median(example_list)
+print(x)
+
+x = statistics.median_low(example_list)
+print(x)
+
+x = statistics.median_high(example_list)
+print(x)
+
+x = statistics.mode([1,1,2,3,4,3,3,3,3])
+print(x)
+
+x = statistics.mode(["a","b","c","d","d","a","a",])
+print(x)
+
+x = statistics.pstdev([2,2,2,6])
+print(x)
+
+x = statistics.pvariance([2,2,2,6])
+print(x)
+
+x = statistics.stdev([2,2,2,6])
+print(x)
+
+x = statistics.variance([2,2,2,6])
+print(x)

day-039/itertools-starmap-demo.py

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+#计算平均数
+>>> statistics.mean([1, 2, 3, 4, 5])
+
+>>> from fractions import Fraction as F
+>>> statistics.mean([F(4, 7), F(4, 21), F(5, 4), F(1, 4)])
+
+>>> from decimal import Decimal as D
+>>> statistics.mean([D("0.5"), D("0.78"), D("0.88"), D("0.988")])
+
+
+#计算调和平均数
+>>> statistics.harmonic_mean([4, 5, 7])
+
+
+#计算中值
+>>> statistics.median([1, 4, 7])
+
+>>> statistics.median([1, 4, 7, 10])
+
+
+#计算中小值
+>>> statistics.median_low([1, 4, 7])
+
+>>> statistics.median_low([1, 4, 7, 10])
+
+
+#计算中大值
+>>> statistics.median_high([1, 4, 7])
+
+>>> statistics.median_high([1, 4, 7, 10])
+
+
+#计算中位数
+>>> statistics.median_grouped([1, 2, 2, 3, 4, 4, 4, 4, 4, 5])
+
+>>> statistics.median_grouped([3, 4, 4, 5, 6], interval=1)
+
+>>> statistics.median_grouped([1, 3, 5, 5, 7], interval=2)
+
+
+#计算众数
+>>> statistics.mode([1, 1, 2, 3, 3, 3, 3, 4])
+
+>>> statistics.mode(["red", "blue", "blue", "blue", "green", "green", "red"])