Python help: SyntaxWarning: 'str' object is not callable

Gary8682 :

Learning python. and I got an error, searched online but I still don't understand why. can somebody help?

code:

 length = float(input("please input the length: "))
unit = input("please input the unit: ")
if unit == "in" or "inch":
    length_b = float(length / 2.54)
    print("%f inch = %f cm"(length, length_b))
elif unit == "cm":
    length_b = float(length * 2.54)
    print("%f cm = %f inch"(length, length_b))
else:
    print("calculation failed")

and I got this error:

test.py:143: SyntaxWarning: 'str' object is not callable; perhaps you missed a comma?
  print("%f inch = %f cm"(length, length_b))
test.py:146: SyntaxWarning: 'str' object is not callable; perhaps you missed a comma?
  print("%f cm = %f inch"(length, length_b))

thanks~

Sheri :

You have to use % in your print statements like this:

length = float(input("please input the length: "))
unit = input("please input the unit: ")
if unit == "in" or unit == "inch":
    length_b = float(length / 2.54)
    print("%f inch = %f cm"%(length, round(length_b,6)))
elif unit == "cm":
    length_b = float(length * 2.54)
    print("%f cm = %f inch"%(length, round(length_b,6)))
else:
    print("calculation failed")

Bonus:You can use format() function easily try this:

length = float(input("please input the length: "))
unit = input("please input the unit: ")
if unit == "in" or unit == "inch":
    length_b = float(length / 2.54)
    print("inch is {} and cm is {}".format(length, length_b))
elif unit == "cm":
    length_b = float(length * 2.54)
    print("cm is {} and inch is {}".format(length, length_b))
else:
    print("calculation failed")

Output:

please input the length: 5                                                                                            
please input the unit: in                                                                                             
inch is 5.0 and cm is 1.968504