python - 创建字典并使用相应的键聚合值

Question

我的问题是找到每个州的上午 9 点湿度的最高值（存储在第 12 列，从零开始）。数据集如下所示：

Date,State,City,Station Code,Minimum temperature (C),Maximum temperature (C),Rainfall (mm),Evaporation (mm),Sunshine (hours),Direction of maximum wind gust,Speed of maximum wind gust (km/h),9am Temperature (C),9am relative humidity (%),3pm Temperature (C),3pm relative humidity (%)
2017-12-01,NSW,Wollongong,068228,19.0,22.9,0,,,NE,59,21.4,81,21.9,80
2017-12-01,QLD,Brisbane,040913,21.8,28.0,0.2,5.6,12.4,E,26,26.6,65,27.1,64
2017-12-01,VIC,Melbourne,086338,21.5,23.5,1.8,11.4,0.0,N,41,21.8,92,18.9,98
2017-12-02,QLD,Gold Coast,040764,22.4,28.4,0,,,N,44,27.6,69,28.0,72
2017-12-02,NSW,Wollongong,068228,17.7,26.6,0,,,W,87,19.9,82,18.1,83
2017-12-02,QLD,Brisbane,040913,22.3,29.4,0,8.0,9.2,NNE,31,26.9,64,26.8,65
2017-12-02,NSW,Canberra,070351,17.7,19.6,35.2,,,NNW,65,17.8,99,16.0,88
2017-12-02,NSW,Newcastle,061055,19.3,28.2,0,,,NW,54,24.0,100,27.3,90
2017-12-02,VIC,Melbourne,086338,14.7,16.4,20.6,3.0,0.0,SSW,56,15.1,97,16.1,93
2017-12-02,SA,Adelaide,023034,15.0,20.4,0.2,4.6,5.0,SSW,57,17.8,52,18.1,59
2017-12-02,NSW,Albury,072160,18.4,20.6,49.6,,,NNE,39,18.5,96,20.1,76
2017-12-03,VIC,Ballarat,089002,8.1,14.4,13.6,,,S,50,10.1,94,13.3,68
2017-12-03,NSW,Wollongong,068228,16.7,24.7,7.2,,,WNW,44,19.7,63,20.7,70
2017-12-03,VIC,Geelong,087184,11.5,17.5,5.8,,,SSW,50,14.0,93,13.6,86
2017-12-03,VIC,Bendigo,081123,10.5,19.8,2.4,,,SSW,48,13.8,65,17.4,46
2017-12-03,WA,Perth,009021,20.1,36.0,0,15.8,4.6,E,70,29.0,19,34.8,12
2017-12-03,QLD,Toowoomba,041529,17.0,25.5,19.8,,,NNW,31,20.0,80,24.3,55
2017-12-03,NSW,Canberra,070351,12.2,19.9,18.4,,,NW,48,13.8,85,19.3,61
2017-12-03,NSW,Newcastle,061055,16.8,27.2,9.4,,,NNW,52,20.7,100,26.3,78
2017-12-03,QLD,Sunshine C,040861,22.1,28.1,3.0,,,NE,35,26.9,68,24.6,91
2017-12-03,QLD,Gold Coast,040764,22.2,27.8,4.0,,,NNW,41,25.5,78,25.3,86
2017-12-03,SA,Adelaide,023034,12.8,19.9,0.6,6.2,5.7,S,50,16.2,52,15.9,65
2017-12-03,NSW,Albury,072160,13.7,22.3,29.6,,,W,39,14.9,83,21.8,43
2017-12-03,VIC,Melbourne,086338,11.5,17.1,43.8,4.8,2.4,S,44,13.2,79,16.5,64
2017-12-03,QLD,Brisbane,040913,23.0,30.4,0.8,7.0,4.4,NE,22,27.0,60,28.6,64
2017-12-04,QLD,Toowoomba,041529,17.1,20.1,0.2,,,SW,28,18.2,77,18.6,73
2017-12-04,VIC,Geelong,087184,12.1,17.7,3.8,,,S,39,14.8,83,14.9,92
2017-12-04,QLD,Gold Coast,040764,20.6,25.6,0,,,SSE,35,24.0,99,18.7,100
2017-12-04,VIC,Ballarat,089002,9.0,16.0,0,,,S,44,10.7,98,13.3,70
2017-12-04,NSW,Albury,072160,12.0,22.7,0,,,NE,54,16.2,50,20.8,37
2017-12-04,SA,Adelaide,023034,13.4,21.5,0.2,6.6,8.3,SW,46,16.6,57,20.0,45
2017-12-04,QLD,Townsville,032040,23.9,31.3,5.0,,,ENE,35,28.5,72,30.7,62
2017-12-04,NSW,Wollongong,068228,14.7,18.7,4.6,,,SSW,52,16.3,83,15.6,92
2017-12-04,NT,Darwin,014015,24.4,35.3,0.2,0.6,9.4,NW,28,29.3,69,34.6,45
2017-12-04,QLD,Sunshine C,040861,19.5,25.8,16.6,,,SSW,30,25.1,64,21.1,93
2017-12-04,NSW,Newcastle,061055,17.4,19.8,0,,,SSW,50,19.4,100,17.1,100
2017-12-04,NSW,Canberra,070351,10.7,15.7,0.2,,,S,28,11.4,90,12.4,87
2017-12-04,VIC,Melbourne,086338,12.4,17.5,5.4,5.0,0.5,SSE,37,15.9,70,17.5,67
2017-12-04,VIC,Bendigo,081123,10.3,19.1,0.2,,,SSE,44,14.0,64,16.8,47
2017-12-04,WA,Perth,009021,19.5,24.6,5.6,8.4,0.9,S,28,20.1,89,23.1,70
2017-12-04,QLD,Cairns,031011,23.4,31.8,4.0,,,SSE,50,29.6,71,30.8,73
2017-12-04,QLD,Brisbane,040913,20.8,28.0,0,5.2,3.1,W,26,27.0,61,21.2,87
2017-12-05,WA,Perth,009021,19.0,28.0,0,2.8,12.8,WSW,43,24.2,53,26.0,51
2017-12-05,NSW,Wollongong,068228,15.4,21.8,5.0,,,SSW,69,18.2,75,19.3,68
2017-12-05,VIC,Ballarat,089002,6.9,19.3,0,,,SE,44,12.9,86,17.7,63
2017-12-05,QLD,Sunshine C,040861,19.5,26.5,60.6,,,WSW,63,22.7,76,17.8,82
2017-12-05,NSW,Albury,072160,10.6,25.6,1.8,,,S,31,18.4,58,24.7,42
2017-12-05,VIC,Geelong,087184,8.6,20.4,1.4,,,SE,43,16.8,84,20.2,69
2017-12-05,NT,Darwin,014015,28.0,35.5,0,6.4,12.0,NW,28,30.6,64,33.4,55
2017-12-05,VIC,Melbourne,086338,10.8,22.8,1.8,1.2,6.9,ESE,39,16.7,71,21.2,54
2017-12-05,VIC,Bendigo,081123,9.9,24.8,0.2,,,SE,37,17.0,58,24.3,37
2017-12-05,QLD,Cairns,031011,22.0,34.2,19.0,,,SE,33,30.1,64,32.7,39
2017-12-05,QLD,Townsville,032040,22.7,34.7,0,,,ENE,41,29.6,44,29.4,74
2017-12-05,SA,Adelaide,023034,12.2,20.9,0,5.2,10.2,WSW,41,17.6,53,19.7,49
2017-12-05,NSW,Newcastle,061055,16.6,20.5,0.2,,,SSW,56,17.8,100,19.1,100
2017-12-05,QLD,Gold Coast,040764,18.4,26.7,33.8,,,SE,31,22.9,91,26.2,77
2017-12-05,QLD,Toowoomba,041529,15.4,26.0,1.0,,,WSW,39,19.6,72,25.0,34
2017-12-05,NSW,Canberra,070351,11.4,20.0,6.6,,,SE,46,15.5,70,17.6,58
2017-12-06,VIC,Bendigo,081123,12.1,26.9,0,,,W,33,18.7,63,25.6,30
2017-12-06,NSW,Canberra,070351,11.9,20.2,5.2,,,WNW,50,15.3,67,17.8,63
2017-12-06,WA,Perth,009021,16.7,28.9,0,10.6,13.2,SSE,50,21.8,40,28.6,24
2017-12-06,VIC,Melbourne,086338,13.6,21.3,0,5.0,7.1,SSW,33,17.3,70,20.3,63
2017-12-06,QLD,Cairns,031011,21.4,31.6,0.2,,,NE,31,29.3,64,30.7,65
2017-12-06,QLD,Sunshine C,040861,15.5,29.7,8.0,,,NNE,35,24.9,41,28.9,40
2017-12-06,NSW,Newcastle,061055,16.7,27.2,0,,,WNW,54,20.3,100,25.4,
2017-12-06,QLD,Townsville,032040,23.9,33.2,0,,,NE,33,30.0,67,31.9,48
2017-12-06,NT,Darwin,014015,26.4,34.8,0,7.6,10.4,WNW,33,30.9,70,33.8,51
2017-12-06,QLD,Brisbane,040913,17.8,31.8,,5.0,13.0,WSW,30,26.8,32,30.9,23
2017-12-06,NSW,Wollongong,068228,16.9,25.1,0,,,SW,43,19.4,63,20.9,59
2017-12-06,SA,Adelaide,023034,13.7,21.4,0,7.0,13.1,SW,46,17.7,54,21.2,46
2017-12-06,QLD,Toowoomba,041529,12.9,26.7,0,,,WNW,50,20.4,40,25.9,22
2017-12-06,NSW,Albury,072160,12.3,26.6,2.0,,,WNW,44,18.5,57,24.6,38
2017-12-06,QLD,Gold Coast,040764,17.6,30.7,1.0,,,NW,41,26.1,37,30.0,23
2017-12-06,VIC,Ballarat,089002,11.2,21.3,0,,,SE,46,14.9,85,19.9,60
2017-12-06,VIC,Geelong,087184,14.1,21.0,0,,,S,33,17.0,82,20.1,67
2017-12-07,NSW,Wollongong,068228,17.7,30.1,0.4,,,NNW,41,24.8,45,23.4,63
2017-12-07,VIC,Bendigo,081123,9.3,24.6,0,,,WNW,37,18.3,46,22.1,39
2017-12-07,QLD,Townsville,032040,26.6,33.1,0,,,NNE,35,29.8,64,32.0,51
2017-12-07,QLD,Gold Coast,040764,16.0,28.5,0,,,ENE,24,27.3,56,27.0,62
2017-12-07,QLD,Sunshine C,040861,15.7,29.8,0,,,NE,28,27.5,36,28.8,45
2017-12-07,VIC,Melbourne,086338,11.6,21.9,0,4.4,7.0,SSW,39,16.9,65,21.3,48
2017-12-07,VIC,Ballarat,089002,6.6,19.2,0.2,,,WSW,39,13.2,94,18.0,52
2017-12-07,QLD,Brisbane,040913,17.4,33.1,0,10.0,13.1,ENE,24,27.6,37,30.7,32
2017-12-07,QLD,Cairns,031011,22.9,31.5,0,,,NE,30,29.1,71,30.9,67
2017-12-07,VIC,Geelong,087184,9.8,22.7,0,,,SSW,41,15.7,88,18.2,69
2017-12-07,WA,Perth,009021,14.6,29.8,0,12.2,13.2,ESE,46,20.8,45,28.6,21
2017-12-07,NSW,Albury,072160,11.5,29.1,0,,,W,56,20.7,57,28.2,30
2017-12-07,NSW,Canberra,070351,8.7,26.7,0.2,,,WNW,54,18.5,56,25.4,31
2017-12-07,SA,Adelaide,023034,11.5,19.3,1.2,7.4,4.2,SSW,52,14.0,84,18.5,65
2017-12-07,NT,Darwin,014015,28.2,34.5,0,8.0,9.9,NW,35,31.4,67,33.0,58
2017-12-07,QLD,Toowoomba,041529,15.8,29.9,0,,,WNW,30,24.4,33,29.2,20

到目前为止，我已经尝试过：

humidity = {}
states= {}
is_first_line = True

for row in open("climate_data_Dec2017.csv"):
  if is_first_line:
    is_first_line = False
  else:
    values = row.split(",")
    humidity_at_nine = values[12]
    states = values[1]
  print(states, ":", float(humidity_at_nine))

所以我为状态和湿度创建了一个字典，但我无法找到最大湿度值，然后将它与一个状态对应起来。我还做了 if 函数来清除第一行，然后将所有值拆分以通过索引找到湿度和状态值。我试过做 max(humanity_at_nine) 但它说它不起作用，因为它不是可迭代的或其他东西，或者是 float/str？

我想要的答案是：

NSW : 100.0
NT : 70.0
QLD : 99.0
SA : 84.0
VIC : 98.0
WA : 89.0 

标签： python

Answer 1

使用 csv 模块csv.DictReader。

演示：

import csv
with open(filename) as infile:
    reader = csv.DictReader(infile, delimiter=",")
    d = {}
    for i in reader:
        if i["State"] not in d:
            d[i["State"]] = []
        d[i["State"]].append(float(i["9am relative humidity (%)"]))
print(dict((k, max(v)) for k,v in d.items()))

输出：

{'VIC': 98.0, 'WA': 89.0, 'QLD': 99.0, 'NT': 70.0, 'SA': 84.0, 'NSW': 100.0}