1、新建一个空白的Python文档。
2、首先初步输入代码要求计算机提示用户输入数字，并且会自动转换为里面。
但是这个是错误的，因为metres * 100不是字符串。
metres = input("Please enter the metres that you want to transfer into centimetres:")
print(metres + "m" + "=" + metres * 100 + "cm")
3、加了STR后，还是错误，因为METRES是数字，数字要和数字相乘。
metres = input("Please enter the metres that you want to transfer into centimetres:")
print(metres + "m" + "=" + str(metres * 100) + "cm")
4、metres = input("Please enter the metres that you want to transfer into centimetres:")
print(metres + "m" + "=" + str(float(metres) * 100) + "cm")
这个才是正确的，可以键入数字检查是否可以执行。
5、为了让程序观看方便，定义变量cm。
metres = input("Please enter the metres that you want to transfer into centimetres:")
cm = float(metres) * 100
print(metres + " m " + " = " + str(cm) + " cm "
6、也可以用.format()，这样修改起来会非常方便。
metres = input("Please enter the metres that you want to transfer into centimetres:")
cm = float(metres) * 100
print("{} m = {} cm" .format(metres, cm))
