I am stuck in while True loop

Question

Python 2.7. I am new to Python and I am stuck with while True loop. Simple program to calculate salary. When 'standard' entered as a letter, it catches the error and jumps again to the line 'Enter your rate'. I want it to be repeated only where the error was captured and not starting to input all info all over again. Can someone help please?

while True:
 try:
 rate = float(raw_input("Enter your rate: "))
 error = float(rate)
 standard = float(raw_input("Enter total standard hours 100%: "))
 error = float(standart) 
 except:
 print 'Not a number'
 continue 
 else:
 sum = standard * rate 
 print sum

Thank you in advance.

• ThunderHorn: add break in the end of else, after print sum

Answer 1

while True:
 try:
 rate = float(raw_input("Enter your rate: "))
 standard = float(raw_input("Enter total standard hours 100%: "))
 except ValueError:
 print 'Not a number' 
 else:
 sum = standard * rate 
 print sum
 break

You need to add a break at the end. Also you dont need to write error = float(..) when you are already trying to typecaste it in the input step.

Also, there is a typo in the line error = float(standart) . This will cause it to give exceptions forever.

Another good practice is to specify the type of error you expect ( ValueError ). This would help prevent things like typos.

Answer 2

Try splitting standard and rate out of the same loop, like so.

def get_input(text):
 while 1:
 try:
 value = float(raw_input(text))
 break
 except:
 print 'Not a Number'
 return value
rate = get_input("Enter your rate: ")
standard = get_input("Enter total standard hours 100%: ")
sum = standard * rate
print(sum)

This way only the value that failed will be re-queried.

• Max V: It does make sense and it did work. Thank you. Can you please only explain why did you put '1' after 'while'?
• Sam Kowalski: I'm glad it worked. In python 1 will evaluate as True, and 0 as false. So while 1 is equivalent to while True.

Answer 3

In your code continue instruction is not needed, as else instruction is executed only if no exception has been thrown.

But to exit the loop in the "positive" case, add break instruction after print sum.

And one more remark: Change standart to standard.

Answer 4

while True:
try:
 rate = float(raw_input("Enter your rate: "))
 standard = float(raw_input("Enter total standard hours 100%: "))
except ValueError:
 print( 'Not a number' )
else:
 sum = standard * rate 
 print(sum)
 break