[英]Python and pandas: Convert a column in CSV file to integer
我的要求是读取一个带有列的 csv 文件:日期、最高温度 (TMAX)、最低温度 (TMIN) 后来我需要按季度汇总并绘制条形图。
我正在使用下面的代码,但它不起作用。
#importing necessary libraries
import pandas as pd
import matplotlib.pyplot as plt
#Reading the file using pandas
df = pd.read_csv(r"C:\Users\home\Downloads\2285297.csv", parse_dates = ['DATE'])
# Reading each column
np_maxtemp= df.loc[:,['TMAX']]
np_mintemp= df.loc[:,['TMIN']]
np_date= df.loc[:,['DATE']]
#Summarizing Max temp by each quarter
df['np_quarter'] = pd.PeriodIndex(df.DATE, freq='Q')
#It gives me list of all quarters 0 2010Q1 1 2010Q2
avg_tmax=df.groupby(by=['np_quarter'])['TMAX'].mean()
avg_tmin=df.groupby(by=['np_quarter'])['TMIN'].mean()
#It gives me averages by quarter
# Then I want to plot with quarters on x-axis and temperature bar plots on y-axis
plt.plot(df['np_quarter'])
plt.ylabel(avg_prec)
plt.show()
第一行本身给出了一个错误:TypeError: float() 参数必须是字符串或数字,而不是“期间”
如何将这些季度转换为字符串并在 y 轴上绘制平均温度?
STATION DATE PRCP TMAX TMIN np_quarter
0 USW00012921 2010-12-01 0.0 65.0 29.0 2010Q4
1 USW00012921 2010-12-02 0.0 71.0 37.0 2010Q4
2 USW00012921 2010-12-03 0.0 76.0 44.0 2010Q4
3 USW00012921 2010-12-04 0.0 79.0 55.0 2010Q4
4 USW00012921 2010-12-05 0.0 60.0 41.0 2010Q4
5 USW00012921 2010-12-06 0.0 59.0 36.0 2010Q4
6 USW00012921 2010-12-07 0.0 60.0 36.0 2010Q4
7 USW00012921 2010-12-08 0.0 60.0 37.0 2010Q4
8 USW00012921 2010-12-09 0.0 65.0 31.0 2010Q4
9 USW00012921 2010-12-10 0.0 74.0 39.0 2010Q4
10 USW00012921 2010-12-11 0.0 75.0 43.0 2010Q4
11 USW00012921 2010-12-12 0.0 60.0 34.0 2010Q4
12 USW00012921 2010-12-13 0.0 60.0 29.0 2010Q4
13 USW00012921 2010-12-14 0.0 72.0 38.0 2010Q4
14 USW00012921 2010-12-15 0.0 76.0 46.0 2010Q4
15 USW00012921 2010-12-16 0.0 64.0 48.0 2010Q4
16 USW00012921 2010-12-17 0.0 57.0 41.0 2010Q4
17 USW00012921 2010-12-18 0.0 58.0 34.0 2010Q4
18 USW00012921 2010-12-19 0.0 67.0 34.0 2010Q4
19 USW00012921 2010-12-20 0.0 76.0 48.0 2010Q4
我认为加载文件存在问题,因为它用空格而不是逗号分隔。 我不确定你想绘制什么,但这里是每个季度的平均值(最小值和最大值)。 我还在 PEP8 中建议的操作符周围放置了空格以提高可读性。 如果它不起作用,请告诉我。
#Reading the file using pandas
df = pd.read_csv(r"C:\Users\home\Download\2285297.csv", delim_whitespace=True) # delimiter is whitespace not comma
df['DATE'] = pd.to_datetime(df['DATE'])
# Reading each column
np_maxtemp = df.loc[:, ['TMAX']]
np_mintemp = df.loc[:, ['TMIN']]
np_date = df.loc[:, ['DATE']]
#Summarizing Max temp by each quarter
df['np_quarter'] = pd.PeriodIndex(df.DATE, freq='Q')
#It gives me list of all quarters 0 2010Q1 1 2010Q2
avg_tmax = df.groupby(by=['np_quarter'])['TMAX'].mean()
avg_tmin = df.groupby(by=['np_quarter'])['TMIN'].mean()
#It gives me averages by quarter
# Then I want to plot with quarters on x-axis and temperature bar plots on y-axis
plt.plot([str(avg_tmax.index[0]) + " MAX",
str(avg_tmax.index[0]) + " MIN"],
[avg_tmax[0], avg_tmin[0]],
'o')
plt.ylabel('avg_prec') # change to str
plt.show()
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