Python:在for循环中"断开"if语句

Question

我理解一个人不能"破坏"一个if语句而只能从一个循环中解决,但是,我试图从概念上停止一个if语句,当它在for循环中第一次找到"true"之后.

# Import XML Parser
import xml.etree.ElementTree as ET

# Parse XML directly from the file path
tree = ET.parse('xml file')

# Create iterable item list
items = tree.findall('item')

# Create class for historic variables
class DataPoint:
    def __init__(self, low, high, freq):
        self.low = low
        self.high = high
        self.freq = freq

# Create Master Dictionary and variable list for historic variables
masterDictionary = {}

# Loop to assign variables as dictionary keys and associate their values with them
for item in items:
    thisKey = item.find('variable').text
    thisList = []
    masterDictionary[thisKey] = thisList

for item in items:
    thisKey = item.find('variable').text
    newDataPoint = DataPoint(float(item.find('low').text), float(item.find('high').text), float(item.find('freq').text))
    masterDictionary[thisKey].append(newDataPoint)

diceDictionary = {}
import random
for thisKey in masterDictionary.keys():
    randomValue = random.random()
    diceList = []
    thisList = []
    diceList = masterDictionary[thisKey]
    diceDictionary[thisKey] = thisList
    for i in range(len(diceList)):
        if randomValue <= sum(i.freq for i in diceList[0:i+1]):         
            print 'O', i, 'randomValue', randomValue, 'prob container', sum(i.freq for i in diceList[0:i+1])
            #diceRoll = random.uniform(diceList[i].low, diceList[i].high)
            #diceDictionary[thisKey].append(diceRoll)
        else:
            print 'X', i, 'randomValue', randomValue, 'prob container', sum(i.freq for i in diceList[0:i+1])

masterDictionary中有两个键,每个键分别包含27和29个数据点的列表.因此,循环

for i in range(len(diceList)):

将为每个键从0 - 26和0 - 28运行i.这很好,但是在评估if语句时的问题是,一旦找到它,随后对于以下所有范围项都将成立.这是打印输出:

X 0 randomValue 0.0775612781213 prob container 0.0294117647059
X 1 randomValue 0.0775612781213 prob container 0.0294117647059
X 2 randomValue 0.0775612781213 prob container 0.0294117647059
X 3 randomValue 0.0775612781213 prob container 0.0294117647059
O 4 randomValue 0.0775612781213 prob container 0.147058823529
O 5 randomValue 0.0775612781213 prob container 0.235294117647
O 6 randomValue 0.0775612781213 prob container 0.441176470588
O 7 randomValue 0.0775612781213 prob container 0.588235294118
O 8 randomValue 0.0775612781213 prob container 0.676470588235
O 9 randomValue 0.0775612781213 prob container 0.764705882353
O 10 randomValue 0.0775612781213 prob container 0.794117647059
O 11 randomValue 0.0775612781213 prob container 0.823529411765
O 12 randomValue 0.0775612781213 prob container 0.823529411765
O 13 randomValue 0.0775612781213 prob container 0.852941176471
O 14 randomValue 0.0775612781213 prob container 0.882352941176
O 15 randomValue 0.0775612781213 prob container 0.882352941176
O 16 randomValue 0.0775612781213 prob container 0.911764705882
O 17 randomValue 0.0775612781213 prob container 0.911764705882
O 18 randomValue 0.0775612781213 prob container 0.911764705882
O 19 randomValue 0.0775612781213 prob container 0.911764705882
O 20 randomValue 0.0775612781213 prob container 0.911764705882
O 21 randomValue 0.0775612781213 prob container 0.941176470588
O 22 randomValue 0.0775612781213 prob container 0.941176470588
O 23 randomValue 0.0775612781213 prob container 0.970588235294
O 24 randomValue 0.0775612781213 prob container 0.970588235294
O 25 randomValue 0.0775612781213 prob container 0.970588235294
O 26 randomValue 0.0775612781213 prob container 0.970588235294
O 27 randomValue 0.0775612781213 prob container 0.970588235294
O 28 randomValue 0.0775612781213 prob container 1.0
X 0 randomValue 0.803308376497 prob container 0.0294117647059
X 1 randomValue 0.803308376497 prob container 0.0294117647059
X 2 randomValue 0.803308376497 prob container 0.0294117647059
X 3 randomValue 0.803308376497 prob container 0.0294117647059
X 4 randomValue 0.803308376497 prob container 0.0294117647059
X 5 randomValue 0.803308376497 prob container 0.0294117647059
X 6 randomValue 0.803308376497 prob container 0.0882352941176
X 7 randomValue 0.803308376497 prob container 0.0882352941176
X 8 randomValue 0.803308376497 prob container 0.0882352941176
X 9 randomValue 0.803308376497 prob container 0.117647058824
X 10 randomValue 0.803308376497 prob container 0.147058823529
X 11 randomValue 0.803308376497 prob container 0.205882352941
X 12 randomValue 0.803308376497 prob container 0.264705882353
X 13 randomValue 0.803308376497 prob container 0.294117647059
X 14 randomValue 0.803308376497 prob container 0.382352941176
X 15 randomValue 0.803308376497 prob container 0.441176470588
X 16 randomValue 0.803308376497 prob container 0.470588235294
X 17 randomValue 0.803308376497 prob container 0.470588235294
X 18 randomValue 0.803308376497 prob container 0.529411764706
X 19 randomValue 0.803308376497 prob container 0.588235294118
X 20 randomValue 0.803308376497 prob container 0.647058823529
X 21 randomValue 0.803308376497 prob container 0.764705882353
O 22 randomValue 0.803308376497 prob container 0.823529411765
O 23 randomValue 0.803308376497 prob container 0.882352941176
O 24 randomValue 0.803308376497 prob container 0.970588235294
O 25 randomValue 0.803308376497 prob container 0.970588235294
O 26 randomValue 0.803308376497 prob container 1.0

任何地方都有一个'X'表示if语句是假的,一旦'O'开始,其余的语句将永远为真,因为prob容器的大小增加(最多1.0).

我正在寻找的是一种方法来告诉我在循环中的if语句一旦找到第一个真正的语句就停止,然后写入字典,然后再次继续外循环.

任何帮助赞赏!

更新:

diceDictionary = {}
x=0 
while x < 3:
    import random
    for thisKey in masterDictionary.keys():
        randomValue = random.random()
        diceList = []
        thisList = []
        diceList = masterDictionary[thisKey]
        diceDictionary[thisKey] = thisList
        for i in range(len(diceList)):
            if randomValue <= sum(i.freq for i in diceList[0:i+1]):         
                print 'O', thisKey, i, 'randomValue', randomValue, 'prob container', sum(i.freq for i in diceList[0:i+1])
                diceRoll = random.uniform(diceList[i].low, diceList[i].high)
                diceDictionary[thisKey].append(diceRoll)
                break
            else:
                print 'X', thisKey, i, 'randomValue', randomValue, 'prob container', sum(i.freq for i in diceList[0:i+1])
    x = x + 1
print diceDictionary

生产:

X inflation 0 randomValue 0.500605733928 prob container 0.0294117647059
X inflation 1 randomValue 0.500605733928 prob container 0.0294117647059
X inflation 2 randomValue 0.500605733928 prob container 0.0294117647059
X inflation 3 randomValue 0.500605733928 prob container 0.0294117647059
X inflation 4 randomValue 0.500605733928 prob container 0.147058823529
X inflation 5 randomValue 0.500605733928 prob container 0.235294117647
X inflation 6 randomValue 0.500605733928 prob container 0.441176470588
O inflation 7 randomValue 0.500605733928 prob container 0.588235294118
X stock 0 randomValue 0.392225720409 prob container 0.0294117647059
X stock 1 randomValue 0.392225720409 prob container 0.0294117647059
X stock 2 randomValue 0.392225720409 prob container 0.0294117647059
X stock 3 randomValue 0.392225720409 prob container 0.0294117647059
X stock 4 randomValue 0.392225720409 prob container 0.0294117647059
X stock 5 randomValue 0.392225720409 prob container 0.0294117647059
X stock 6 randomValue 0.392225720409 prob container 0.0882352941176
X stock 7 randomValue 0.392225720409 prob container 0.0882352941176
X stock 8 randomValue 0.392225720409 prob container 0.0882352941176
X stock 9 randomValue 0.392225720409 prob container 0.117647058824
X stock 10 randomValue 0.392225720409 prob container 0.147058823529
X stock 11 randomValue 0.392225720409 prob container 0.205882352941
X stock 12 randomValue 0.392225720409 prob container 0.264705882353
X stock 13 randomValue 0.392225720409 prob container 0.294117647059
X stock 14 randomValue 0.392225720409 prob container 0.382352941176
O stock 15 randomValue 0.392225720409 prob container 0.441176470588
X inflation 0 randomValue 0.146182475695 prob container 0.0294117647059
X inflation 1 randomValue 0.146182475695 prob container 0.0294117647059
X inflation 2 randomValue 0.146182475695 prob container 0.0294117647059
X inflation 3 randomValue 0.146182475695 prob container 0.0294117647059
O inflation 4 randomValue 0.146182475695 prob container 0.147058823529
X stock 0 randomValue 0.745100497977 prob container 0.0294117647059
X stock 1 randomValue 0.745100497977 prob container 0.0294117647059
X stock 2 randomValue 0.745100497977 prob container 0.0294117647059
X stock 3 randomValue 0.745100497977 prob container 0.0294117647059
X stock 4 randomValue 0.745100497977 prob container 0.0294117647059
X stock 5 randomValue 0.745100497977 prob container 0.0294117647059
X stock 6 randomValue 0.745100497977 prob container 0.0882352941176
X stock 7 randomValue 0.745100497977 prob container 0.0882352941176
X stock 8 randomValue 0.745100497977 prob container 0.0882352941176
X stock 9 randomValue 0.745100497977 prob container 0.117647058824
X stock 10 randomValue 0.745100497977 prob container 0.147058823529
X stock 11 randomValue 0.745100497977 prob container 0.205882352941
X stock 12 randomValue 0.745100497977 prob container 0.264705882353
X stock 13 randomValue 0.745100497977 prob container 0.294117647059
X stock 14 randomValue 0.745100497977 prob container 0.382352941176
X stock 15 randomValue 0.745100497977 prob container 0.441176470588
X stock 16 randomValue 0.745100497977 prob container 0.470588235294
X stock 17 randomValue 0.745100497977 prob container 0.470588235294
X stock 18 randomValue 0.745100497977 prob container 0.529411764706
X stock 19 randomValue 0.745100497977 prob container 0.588235294118
X stock 20 randomValue 0.745100497977 prob container 0.647058823529
O stock 21 randomValue 0.745100497977 prob container 0.764705882353
X inflation 0 randomValue 0.332170052306 prob container 0.0294117647059
X inflation 1 randomValue 0.332170052306 prob container 0.0294117647059
X inflation 2 randomValue 0.332170052306 prob container 0.0294117647059
X inflation 3 randomValue 0.332170052306 prob container 0.0294117647059
X inflation 4 randomValue 0.332170052306 prob container 0.147058823529
X inflation 5 randomValue 0.332170052306 prob container 0.235294117647
O inflation 6 randomValue 0.332170052306 prob container 0.441176470588
X stock 0 randomValue 0.145551106438 prob container 0.0294117647059
X stock 1 randomValue 0.145551106438 prob container 0.0294117647059
X stock 2 randomValue 0.145551106438 prob container 0.0294117647059
X stock 3 randomValue 0.145551106438 prob container 0.0294117647059
X stock 4 randomValue 0.145551106438 prob container 0.0294117647059
X stock 5 randomValue 0.145551106438 prob container 0.0294117647059
X stock 6 randomValue 0.145551106438 prob container 0.0882352941176
X stock 7 randomValue 0.145551106438 prob container 0.0882352941176
X stock 8 randomValue 0.145551106438 prob container 0.0882352941176
X stock 9 randomValue 0.145551106438 prob container 0.117647058824
O stock 10 randomValue 0.145551106438 prob container 0.147058823529
{'inflation': [0.028073642645577577], 'stock': [-0.07388514885974767]}

Answer 1

    if randomValue <= sum(i.freq for i in diceList[0:i+1]):         
        print 'O', i, 'randomValue', randomValue, 'prob container', sum(i.freq for i in diceList[0:i+1])
        break

Break将终止"最近的封闭循环,如果循环有一个则跳过可选的else子句." 外部循环将继续下一次迭代.所以,如果被包围在你没有"突破是否",而是循环的.休息前,你可以设置所有的值从diceList[0:i+1]至diceList[0:len(diceList)+1]为true.