为什么我收到类型错误：“int”在使用 plot function 时不可迭代

Question

for i in range(len(name_of_output_file_list)):
if i==0:
    Power_=pandas.DataFrame(DF_list[i]['GenPwr'][-TofA:].describe())#describe([0.25,0.5,0.75,0.95])
    Power_.columns=[Velocity_[i]]
    Power_=Power_.T
else:
    Power_temp=pandas.DataFrame(DF_list[i]['GenPwr'][-TofA:].describe())
    Power_temp.columns=[Velocity_[i]]
    Power_ = pandas.concat([Power_, Power_temp.T])
    Power_.to_csv(ResFolder+'GenPwr.csv',header=True)

**创建了 csv 文件

filenameWPC = root_name_of_output_file+'GenPwr'
figWPC = figure( 1, dpi = 152 )
figWPC.set_size_inches( 6, 4.05 )
subplots_adjust( left=.12, bottom=0.12,right=.95, top=.95, hspace=.02, wspace=.18 )

plt.errorbar(Vel, Power_[str('mean')], yerr=Power_[str('std')], 
dashes=lnsty[0],color=mkclr[0], clip_on=True,marker='o')

xlim(3,25.)
ylim(0,5500)
xlabel( 'Wind speed [m/s]' )   #NOVO
ylabel( 'Turbine Power [kW] '  )   #NOVO
yticks(np.arange(0,5500.01,500))
xticks(np.arange(3,25.01,1.))
grid(True)
savefig( ResFolder+filenameWPC +'.pdf')

我尝试创建一个 Plot 并生成一个 pdf 输出文件。 但是得到一个类型错误： int not iterable in the line

 plt.errorbar(Vel, Power_[str('mean')], yerr=Power_[str('std')], 
dashes=lnsty[0],color=mkclr[0], clip_on=True,marker='o')