I query user input which is expected to be an int by using int(raw_input(...))
However when the user doesn't enter an integer, i.e. just hits return, I get a ValueError.
def inputValue(inputMatrix, rangeRows, rangeCols, defaultValue, playerValue):rowPos = int(raw_input("Please enter the row, 0 indexed."))colPos = int(raw_input("Please enter the column, 0 indexed."))while True:#Test if valid row col position and position does not have default valueif rangeRows.count(rowPos) == 1 and rangeCols.count(colPos) == 1 and inputMatrix[rowPos][colPos] == defaultValue:inputMatrix[rowPos][colPos] = playerValuebreakelse:print "Either the RowCol Position doesn't exist or it is already filled in."rowPos = int(raw_input("Please enter the row, 0 indexed."))colPos = int(raw_input("Please enter the column, 0 indexed."))return inputMatrixI tried to be smart and use try and except to catch the ValueError, print a warning to the user and then call the inputValue() again. Then it works when the user enters return to the query but falls over when the user correctly then enters an integer
Below is the part of the amended code with the try and except:
def inputValue(inputMatrix, rangeRows, rangeCols, defaultValue, playerValue):try:rowPos = int(raw_input("Please enter the row, 0 indexed."))except ValueError:print "Please enter a valid input."inputValue(inputMatrix, rangeRows, rangeCols, defaultValue, playerValue) try:colPos = int(raw_input("Please enter the column, 0 indexed."))except ValueError:print "Please enter a valid input."inputValue(inputMatrix, rangeRows, rangeCols, defaultValue, playerValue) Best Answer
A quick and dirty solution is:
parsed = Falsewhile not parsed:try:x = int(raw_input('Enter the value:'))parsed = True # we only get here if the previous line didn't throw an exceptionexcept ValueError:print 'Invalid value!'This will keep prompting the user for input until parsed is True which will only happen if there was no exception.
Instead of calling inputValue recursively, you need to replace raw_input with your own function with validation and retry. Something like this:
def user_int(msg):try:return int(raw_input(msg))except ValueError:return user_int("Entered value is invalid, please try again")Is something like this what you're going for?
def inputValue(inputMatrix, defaultValue, playerValue):while True:try:rowPos = int(raw_input("Please enter the row, 0 indexed."))colPos = int(raw_input("Please enter the column, 0 indexed."))except ValueError:continueif inputMatrix[rowPos][colPos] == defaultValue:inputMatrix[rowPos][colPos] = playerValuebreakreturn inputMatrixprint inputValue([[0,0,0], [0,0,0], [0,0,0]], 0, 1)You were right to try and handle the exception, but you don't seem to understand how functions work... Calling inputValue from within inputValue is called recursion, and it's probably not what you want here.