python中两种浮点值的比较
我是python编程新手 我编写了一些简单的python代码,如下所示:python中两种浮点值的比较,python,comparison,Python,Comparison,我是python编程新手 我编写了一些简单的python代码,如下所示: #!/usr/bin/python import sys def reducer(): bigSale = 0 oldKey = None for line in sys.stdin: data = line.strip().split("\t") if len(data) != 2: continue thisKey
#!/usr/bin/python
import sys
def reducer():
bigSale = 0
oldKey = None
for line in sys.stdin:
data = line.strip().split("\t")
if len(data) != 2:
continue
thisKey, thisSale = data
print oldKey,bigSale,thisKey,thisSale
if not oldKey:
oldKey = thisKey
bigSale = thisSale
print "This is first if and value of oldKey and bigSale are ",oldKey," ",bigSale
elif oldKey and oldKey != thisKey:
print "{0}\t{1}".format(oldKey, bigSale)
oldKey = thisKey
bigSale = 0
elif(oldKey and oldKey == thisKey and thisSale > bigSale):
print "Observe the expression : ", thisSale, " > " , bigSale , " has a boolean value of ", thisSale > bigSale
print "This is the second elif construct and value of bigSale before assignment is ",bigSale
bigSale = thisSale
print "This is the second elif construct and value of bigSale after assignment is ",bigSale
print "Now the new value of oldKey and bigSale are: ",oldKey," ",bigSale
if oldKey != None and thisSale > bigSale:
print "{0}\t{1}".format(oldKey, bigSale)
def main():
reducer()
main()
我正在传递以下数据作为输入:
Anchorage 22.36
Anchorage 298.86
Anchorage 6.38
Aurora 117.81
Austin 327.75
Austin 379.6
Austin 469.63
Boston 418.94
Buffalo 483.82
Chandler 344.09
Chandler 414.08
Chicago 31.08
Corpus Christi 25.38
Fort Wayne 370.55
Fort Worth 153.57
Fort Worth 213.88
Fremont 222.61
Fresno 466.64
Greensboro 290.82
Honolulu 345.18
Houston 309.16
Indianapolis 135.96
Las Vegas 53.26
Las Vegas 93.39
Lincoln 136.9
Madison 16.78
Minneapolis 182.05
Newark 39.75
New York 296.8
Norfolk 189.01
Omaha 235.63
Omaha 255.68
Philadelphia 351.31
Pittsburgh 475.26
Pittsburgh 493.51
Portland 108.69
Reno 80.46
Reno 88.25
Riverside 15.41
Riverside 252.88
San Bernardino 170.2
San Diego 66.08
San Francisco 260.65
San Jose 214.05
San Jose 215.82
Spokane 287.65
Spokane 3.85
Stockton 247.18
Tulsa 205.06
Virginia Beach 376.11
当我在调试语句的帮助下看到输出时,我发现浮点比较没有按预期进行请查找我在样本数据上运行代码时获得的以下输出片段: 无0.22.36 这是第一次,如果oldKey和bigSale的价值为22.36 锚地22.36锚地298.86 观察表达式:
298.86>22.36
的布尔值为True
这是第二个elif
结构,转让前bigSale的价值为22.36
这是第二个elif
结构,转让后bigSale的价值为298.86
现在oldKey和bigSale的新值是:Anchorage 298.86
锚地298.86锚地6.38
观察表达式:6.38>298.86的布尔值为True
这是第二个elif结构,转让前bigSale的价值为298.86
这是第二个elif结构,转让后bigSale的价值为6.38
现在oldKey和bigSale的新值是:Anchorage 6.38
有人能帮我找出哪里做错了吗?看来你面临的问题是,你将
字符串
与字符串
进行比较,而不是将浮点
与浮点
比较字符串时,确实6.38>298.86
的布尔值为True
,因为6大于2
为了将float
与float
进行比较,需要使用float(str)
e、 g
例如,您可以使用以下样式更改代码(在比较浮点值的所有情况下):
elif(oldKey and oldKey == thisKey and float(thisSale) > float(bigSale)):
此外,还可以将变量的值指定为float,而不是string。再次使用铸造浮动使用浮动(str\u编号)
有关python数据类型转换的详细信息:
elif(oldKey and oldKey == thisKey and float(thisSale) > float(bigSale)):