Python 巨蟒:“;“爆发”;for循环中if语句的类型
我知道不能“中断”if语句,只能从循环中中断,但是,我试图从概念上阻止if语句在其第一次在for循环中找到“true”后进行求值Python 巨蟒:“;“爆发”;for循环中if语句的类型,python,if-statement,for-loop,break,Python,If Statement,For Loop,Break,我知道不能“中断”if语句,只能从循环中中断,但是,我试图从概念上阻止if语句在其第一次在for循环中找到“true”后进行求值 # 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') #
# 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])
将从0-26和0-28为每个键运行i。这很好,但是当计算if语句时的问题是,一旦找到它,它将随后对以下所有范围项都为真。以下是打印输出:
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
只要有一个“X”就意味着if语句为false,并且一旦一个“O”开始,其余语句将始终为true,因为prob容器的大小不断增加(高达1.0)
我要寻找的是一种方法,告诉循环中的if语句在找到第一个true语句后停止,然后写入字典,然后再次继续外部循环
感谢您的帮助
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
if randomValue一种方法是在内部代码中引发异常,并在for循环中捕获它,然后继续循环。据我所知,您试图为循环的其余部分保存if比较。我认为您必须将现有的循环拆分为两个循环,一个执行if语句并找到分区点,第二个简单地跳过比较。您可以在循环外部的变量上保持当前的i,然后在第二个循环中从该点继续。那么您知道该语句为真的条件是什么?我认为可能是“如果最后一个语句为真”,但在示例输出中,您最终返回到False
无论哪种方式,考虑将此作为对IF的第一种条件:
if (you don't already know it's True) and (the condition you currently evaluate):
<Do calculations>
如果(您还不知道这是真的)和(您当前评估的情况):
如果第一部分的计算结果为False(即,您已经知道它是True
),Python不应该计算和
的第二项(因为它现在不能是True
)并继续计算。您只需要添加另一个else子句(因此可以将else
设置为elif
)并在那里处理它
注意:这种方法可能有点麻烦,这取决于您需要做什么来确定您是否已经知道该语句是True
:\如果您确定要中断If语句的代码块,并且如果只有“break”可以工作,您可以将“break”放在在需要的地方,然后通过一次迭代将整个if语句块放入循环中。我尝试了您最初建议的中断,它确实起了作用(请参见上面的更新),但我似乎无法在经过循环时将所选值附加到字典列表中(请注意while循环添加)。字典的每个键列表中应该有3个值,但正如您所看到的,只有最后一次迭代出现。我似乎在每次通过时都会覆盖,而不是追加。有什么想法吗?哦,没关系。我将此列表移到循环之外,这阻止了它被覆盖。我的疏忽。谢谢
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]}
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
if (you don't already know it's True) and (the condition you currently evaluate):
<Do calculations>