如何使用Python知道用户是否按下了Enter键

Question

如何知道用户是否使用Python按下了Enter键？

例如：

user = raw_input("type in enter")
if user == "enter":
    print "you pressed enter"
else:
    print "you haven't pressed enter"

Answer 1

user_input=input("ENTER SOME POSITIVE INTEGER : ")
if((not user_input) or (int(user_input)<=0)):    
  print("ENTER SOME POSITIVE INTEGER GREATER THAN ZERO") #print some info
  import sys        #import
  sys.exit(0)       #exit program 
'''
#(not user_input) checks if user has pressed enter key without entering  
# number.
#(int(user_input)<=0) checks if user has entered any number less than or 
#equal to zero.
'''

Answer 2

正如@jornsharpe所说，正确退出raw_input函数的唯一方法是按enter键。因此，解决方法是检查结果是否包含某些内容：

text = raw_input("type in enter")
if text == "":
    print "you pressed enter"
else:
    print "you typed some text before pressing enter"

我看到的退出raw_input函数的唯一其他方法将引发异常，例如：

• EOFError如果您键入^D
• KeyboardInterrupt如果您键入^C
• 。。。