Question

我正在尝试使用matplotlib创建一个多条形图。

from sqlalchemy import create_engine
import _mssql
from matplotlib import pyplot as plt
import numpy as np


engine = create_engine('mssql+pymssql://sa:california851101@127.0.0.1:1433/AffectV_Test')
connection = engine.connect()
result = connection.execute('SELECT pa.[Date],pa.[Type],(CAST((SUM(pa.Actions_Logged)/SUM(pi.Impressions_Served))*100 AS Decimal(4,4))) AS Daily_Action_Rate from Performance_Actions pa INNER JOIN Performance_Impressions pi ON pa.Alternative = pi.Alternative AND pa.[Date] = pi.[Date] GROUP BY [Type],pa.[Date] ORDER BY pa.[Date] ASC')

click = []
conversion = []
landing = []
xTickMarks = []

for row in result:
    if row[1] == 'click':
        click.append(str(row[2]))
    elif row[1] == 'conversion':
        conversion.append(str(row[2]))
    else:
        landing.append(str(row[2]))
    xTickMarks.append(str(row[0]))



connection.close()

ax = plt.subplot(111)
w = 0.3
ax.bar(xTickMarks-w, click,width=w,color='b',align='center')
ax.bar(xTickMarks, conversion,width=w,color='g',align='center')
ax.bar(xTickMarks+w, landing,width=w,color='r',align='center')
ax.xaxis_date()
ax.autoscale(tight=True)

plt.show()

当我尝试运行代码时出现以下错误：

TypeError                                 Traceback (most recent call last)
<ipython-input-63-8a9e652a1846> in <module>()
     32 ax = plt.subplot(111)
     33 w = 0.3
     ---> 34 ax.bar(xTickMarks-w, click,width=w,color='b',align='center')
     35 ax.bar(xTickMarks, conversion,width=w,color='g',align='center')
     36 ax.bar(xTickMarks+w, landing,width=w,color='r',align='center')

TypeError: unsupported operand type(s) for -: 'list' and 'float'

尝试将列表转换为numpy数组，不用了。

上述代码的结果数据集是：

01/04/2015  click       0.0036
01/04/2015  conversion  0.0010
01/04/2015  landing     0.0058
02/04/2015  click       0.0132
02/04/2015  conversion  0.0014
02/04/2015  landing     0.0104

参考问题Question

Answer 1

如果strings中有xTickMarks，我认为你想要这样做

ax.bar([float(x)-w for x in xTickMarks], ...)

如果xTickMarks由浮点数组成，您也可以

ax.bar([x-w for x in xTickMarks], ...)

或

xTickMarks = np.asarray(xTickMarks)
ax.bar(xTickMarks-w, ...)

Answer 2

xTickMarks是一个列表。

当您尝试从列表中减去浮点数（xTickMarks-w）时，

w = 0.3会引发异常。

如果您尝试从0.3的每个元素中减去xTickMarks，那么您应该使用plonsers方法。

Answer 3

对于 ax.bar（xTickMarks-w，单击，宽度= w，颜色='b'，align ='居中'）这个工作。

您可以尝试这样：

index = np.arrange(len(xTickMarks))
ax = plt.subplot(111)

plt.xticks(index, xTickMarks, fontsize = 9)


w = 0.3
ax.bar(index-w, click,width=w,color='b',align='center')
ax.bar(index, conversion,width=w,color='g',align='center')
ax.bar(index+w, landing,width=w,color='r',align='center')\

这应该有效。

Matplotlib：不支持的操作数类型 - ：'list'和'float'

3 个答案: