文件python中年和月數據的平均溫度

Question

我有一個數據文件，其中包含某種特定格式的數據，並且在處理時有一些額外的行要忽略。 我需要處理數據並根據相同的值計算一個值。

樣本數據：

Average monthly temperatures in Dubuque, Iowa, 
January 1964 through december 1975, n=144

24.7    25.7    30.6    47.5    62.9    68.5    73.7    67.9    61.1    48.5    39.6    20.0
16.1    19.1    24.2    45.4    61.3    66.5    72.1    68.4    60.2    50.9    37.4    31.1
10.4    21.6    37.4    44.7    53.2    68.0    73.7    68.2    60.7    50.2    37.2    24.6
21.5    14.7    35.0    48.3    54.0    68.2    69.6    65.7    60.8    49.1    33.2    26.0
19.1    20.6    40.2    50.0    55.3    67.7    70.7    70.3    60.6    50.7    35.8    20.7
14.0    24.1    29.4    46.6    58.6    62.2    72.1    71.7    61.9    47.6    34.2    20.4
8.4     19.0    31.4    48.7    61.6    68.1    72.2    70.6    62.5    52.7    36.7    23.8
11.2    20.0    29.6    47.7    55.8    73.2    68.0    67.1    64.9    57.1    37.6    27.7
13.4    17.2    30.8    43.7    62.3    66.4    70.2    71.6    62.1    46.0    32.7    17.3
22.5    25.7    42.3    45.2    55.5    68.9    72.3    72.3    62.5    55.6    38.0    20.4
17.6    20.5    34.2    49.2    54.8    63.8    74.0    67.1    57.7    50.8    36.8    25.5
20.4    19.6    24.6    41.3    61.8    68.5    72.0    71.1    57.3    52.5    40.6    26.2

樣本文件來源： http ： //robjhyndman.com/tsdldata/data/cryer2.dat

注意：這里，行代表年份，列代表月份。

我正在嘗試編寫一個函數，它返回給定URL的任意月份的平均溫度。

我試過如下：

def avg_temp_march(f):

   march_temps = []

    # read each line of the file and store the values
    # as floats in a list
    for line in f:
        line = str(line, 'ascii') # now line is a string
        temps = line.split()
    # check that it is not empty.
        if temps != []:
            march_temps.append(float(temps[2]))

    # calculate the average and return it
    return sum(march_temps) / len(march_temps)

avg_temp_march("data5.txt")

但我得到錯誤line = str(line, 'ascii')

TypeError: decoding str is not supported

Answer 1

我認為沒有要求將字符串轉換為字符串。

我嘗試通過一些修改來修復您的代碼：

def avg_temp_march(f):
    # f is a string read from file

    march_temps = []

    for line in f.split("\n"):
        if line == "":  continue
        temps = line.split(" ")
        temps = [t for t in temps if t != ""]

        # check that it is not empty.
        month_index = 2
        if len(temps) > month_index:

            try:
                march_temps.append(float(temps[month_index]))
            except Exception, e:
                print temps
                print "Skipping line:", e
    # calculate the average and return it
    return sum(march_temps) / len(march_temps)

輸出：

['Average', 'monthly', 'temperatures', 'in', 'Dubuque,', 'Iowa,']
Skipping line: could not convert string to float: temperatures
['January', '1964', 'through', 'december', '1975,', 'n=144']
Skipping line: could not convert string to float: through
32.475

基於您的原始問題（在最新編輯之前），我認為您可以通過這種方式解決您的問題。

# from urllib2 import urlopen 
from urllib.request import urlopen #python3

def avg_temp_march(url):
  f = urlopen(url).read()
  data = f.split("\n")[3:] #ingore the first 3 lines
  data = [line.split() for line in data if line!=''] #ignore the empty lines
  data = [map(float, line) for line in data] #Convert all numbers to float
  month_index = 2 # 2 for march
  monthly_sum = sum([line[month_index] for line in data])
  monthly_avg = monthly_sum/len(data)
  return monthly_avg

print avg_temp_march("http://robjhyndman.com/tsdldata/data/cryer2.dat")

Answer 2

使用pandas ，代碼變得更短：

import calendar
import pandas a spd
df = pd.read_csv('data5.txt', delim_whitespace=True, skiprows=2,
                 names=calendar.month_abbr[1:])

現在三月：

>>> df.Mar.mean()
32.475000000000001

並且所有月份：

>>> df.mean()
Jan    16.608333
Feb    20.650000
Mar    32.475000
Apr    46.525000
May    58.091667
Jun    67.500000
Jul    71.716667
Aug    69.333333
Sep    61.025000
Oct    50.975000
Nov    36.650000
Dec    23.641667
dtype: float64