新手刚开始学习Python时容易出现的错误

>>> while True print "hi~"
  File "<stdin>", line 1    
  while True print "hi~"
               ^
SyntaxError: invalid syntax

if spam == 42 print('Hello!')

if spam = 42: print('Hello!')

print('Hello!') 
   print('Howdy!')

if spam == 42: 
print('Hello!') 
print('Howdy!')

 if spam == 42: 
print('Hello!')

spam = ['cat', 'dog', 'mouse'] for i in range(spam): 
     print(spam[i])

spam = 'I have a pet cat.' 
spam[13] = 'r' print(spam)

spam = 'I have a pet cat.' 
spam = spam[:13] + 'r' + spam[14:] print(spam)

numEggs = 12 print('I have ' + numEggs + ' eggs.')

numEggs = 12 print('I have ' + str(numEggs) + ' eggs.')

 numEggs = 12 print('I have %s eggs.' % (numEggs))

print(Hello!') 或者: print('Hello!)

myName = 'Al' print('My name is ' + myName + . How are you?')

foobar = 'Al' print('My name is ' + fooba)

spam = ruond(4.2)

spam = Round(4.2)

spam = 'THIS IS IN LOWERCASE.' spam = spam.lowerr()

>>> 10 * (1/0)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>ZeroDivisionError: integer division or modulo by zero
>>> 4 + git*3
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>NameError: name 'git' is not defined
>>> '2' + 1
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>TypeError: cannot concatenate 'str' and 'int' objects
>>>

>>> while True:
...     try:
...         x = int(raw_input("Please enter a number: "))
...         break...     except ValueError:
...         print "Oops! That was no valid number. Try again..."... 
Please enter a number: x
Oops! That was no valid number. Try again...
Please enter a number: 32x
Oops! That was no valid number. Try again...
Please enter a number: 038

... except (RuntimeError, TypeError, NameError):
...     pass

import systry:
    f = open('myfile.txt')
    s = f.readline()
    i = int(s.strip())
except IOError as e:    
       print "I/O error({0}): {1}".format(e.errno, e.strerror)
except ValueError:    
       print "Could not convert data to an integer."
except:    
       print "Unexpected error:", sys.exc_info()[0]    
       raise

for arg in sys.argv[1:]:    
     try:
        f = open(arg, 'r')    
   except IOError:        
           print 'cannot open', arg    
   else:        
           print arg, 'has', len(f.readlines()), 'lines'
        f.close()

>>> try:
...     raise Exception('spam', 'eggs')
... except Exception as inst:
...     print type(inst)
...     print inst.args
...     print inst
...     x, y = inst.args
...     print 'x =', x
...     print 'y =', y
... 
<type 'exceptions.Exception'>
('spam', 'eggs')
('spam', 'eggs')
x = spam
y = eggs

>>> def mdiv():
...     x = 1/0
... 
>>> try:
...     mdiv()
... except ZeroDivisionError as detail:
...      print 'Handling run-time error:', detail
... 
Handling run-time error: integer division or modulo by zero

>>> class MyError(Exception):
...     def __init__(self, value):
...          self.value = value
...     def __str__(self):
...          return repr(self.value)
... 
>>> try:
...     raise MyError(1+5)
... except MyError as e:
...     print 'My exception occurred, value:', e.value
... 
My exception occurred, value: 6
>>> raise MyError('oops!')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
__main__.MyError: 'oops!'

class Error(Exception):    
    """Base class for exceptions in this module."""
    pass
    
class InputError(Error):    
    """Exception raised for errors in the input.    
    Attributes:        
       expr -- input expression in which the error occurred        
       msg  -- explanation of the error    """

    def __init__(self, expr, msg):        
       self.expr = expr        
       self.msg = msg
class TransitionError(Error):    
    """Raised when an operation attempts a state transition that's not    
       allowed.    
       
       Attributes:        
          prev -- state at beginning of transition        
          next -- attempted new state        
          msg  -- explanation of why the specific transition is not allowed    
       """

    def __init__(self, prev, next, msg):        
        self.prev = prev        
        self.next = next
        self.msg = msg

someVar = 42 def myFunction(): 
   print(someVar) 
   someVar = 100 
   myFunction()

spam = range(10) 
spam[4] = -1

spam = list(range(10)) 
spam[4] = -1

spam = 1
spam++

spam = 1 
spam += 1

class Foo(): def myMethod(): 
       print('Hello!') a = Foo() a.myMethod()