The differences between print in Python2 and Python3

The print() method is provided in both Python2 and Python3 to print information, but the print between the two versions is slightly different

Mainly reflected in the following aspects:

1. In python3, print is a built-in function, and there are many parameters, and print in python2 is a grammatical structure;

2. Python2 can print without parentheses: print 'hello world', Python3 requires parentheses print("hello world")

3. In Python2, input The input string must be quoted. In order to avoid some behaviors that occur when reading non-string types, you have to use raw_input() instead of input()

1. In python3, perhaps developers feel that print has two functions at the same time. The identity was a little uncomfortable, so I only kept the identity of the function:

>>> print 'pythontab.com'
SyntaxError: Missing parentheses in call to 'print'

So you must use parentheses for print in python3, because it is a function.

2. The print function in python3 has multiple parameters. The function prototype is as follows:

print(value1, ..., sep=' ', end='\n', file=sys.stdout, flush=False)

As can be seen from the above method prototype,

1. print can support multiple parameters and support printing multiple strings at the same time ( Among them... represents any number of strings);

2. sep represents what characters are used to connect multiple strings;

3. end represents what characters are added to the end of the string. You can easily set up printing by pointing to this parameter. Without line breaks, the print statement under Python 2. But under Python 3.x, print() becomes a built-in function, and the old method of adding "," will not work.

>>> print("python", "tab", ".com", sep='')
pythontab.com
 
>>> print("python", "tab", ".com", sep='', end='') #就可以实现打印出来不换行
pythontab.com

3. The pitfall of input in Python2

print ("what do you like")
a = input("Enter any content:")
print ("i like",a)

An error will be reported when entering a string, but this problem is solved well in python3.