字符串拼接
df = pd.read_csv(‘ncovtest.csv’)
df.columns=[“city”,“num”]
cityname=df.city
number=df.num
#重点！！！astype不改变原数组数值类型，需重新赋值
number=number.astype(str)
#number1=int(number)
#print（cityname）
print(number.head())
for i in range(0, len(cityname)):
print(’\t’+"{name：’"+ cityname[i] + "’, value: " + number[i] + “},”)