Python - Demo4-- type conversion function

1, str () function: the parameter value into a value type of a string, and returns.

scene:

When using the printing function is used if the link character string of numbers, we need to use str () function converts the value into a string and then using the + operator connection.

Example:

>>> number=12 >>> print('我有'+number+'个苹果') Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: can only concatenate str (not "int") to str

Description:

The above is an example of an error

The reason being given the rearmost row said: Only connect str and str

So: we must have a means to convert int to str can be output.

Therefore: python and the connection string values, we can first value into a string, then the connection

>>> Print ( ' I ' + str (Number The) + ' apple ' )
I have 12 apples

2, int () function: converting a digital value into an integer form character string, and returns.

scene:

When we use the Input () function, we know that all string values ​​returned after input information received from the console INPUT (), if we want the user inputted digital arithmetic operations have to use int () conversion .

Example:

Age = the INPUT >>> ( ' Enter your age: ' )
Enter your Age: 12
>>> type(age)
<class 'str'>
>>> new_age=age+10
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: can only concatenate str (not "int") to str
>>> new_age=int(age)+10
>>> new_age
22

Description:

  • The first line of variable age using the received input () return value;
  • Then we use the python built-in type () function type detection. The type of information returned is: str type
  • We use str directly adding, incorrect report! Error message is: strings and numbers can not be connected to the operation? Viewed as a plus even the string concatenation operator
  • Finally, use int () function to convert a string, success.

Guess you like

Origin www.cnblogs.com/bigbosscyb/p/12317014.html