79 lines
2.1 KiB
Markdown
79 lines
2.1 KiB
Markdown
|
---
|
|||
|
title: How to Convert Strings into Integers in Python
|
|||
|
localeTitle: 如何在Python中将字符串转换为整数
|
|||
|
---
|
|||
|
## 如何在Python中将字符串转换为整数
|
|||
|
|
|||
|
就像内置的`str()`一样,Python也提供了一个方便的内置函数,它将一个字符串对象作为参数并返回相应的整数对象。
|
|||
|
|
|||
|
#### 用法示例:
|
|||
|
|
|||
|
```py
|
|||
|
# Here age is a string object
|
|||
|
age = "18"
|
|||
|
print(age)
|
|||
|
# Converting string to integer
|
|||
|
int_age = int(age)
|
|||
|
print(int_age)
|
|||
|
```
|
|||
|
|
|||
|
产量
|
|||
|
|
|||
|
```py
|
|||
|
18
|
|||
|
18
|
|||
|
```
|
|||
|
|
|||
|
虽然输出在视觉上类似,但你应该记住,第一行打印一个字符串对象,而它旁边的行打印一个整数对象,这将在下一个例子中进一步说明:
|
|||
|
|
|||
|
```py
|
|||
|
age = "18"
|
|||
|
print(age+2)
|
|||
|
```
|
|||
|
|
|||
|
输出:
|
|||
|
|
|||
|
```py
|
|||
|
Traceback (most recent call last):
|
|||
|
File "<stdin>", line 1, in <module>
|
|||
|
TypeError: cannot concatenate 'str' and 'int' objects
|
|||
|
```
|
|||
|
|
|||
|
`The error should make it clear to you that you need to convert the`向其添加内容之前 `The error should make it clear to you that you need to convert the` age\`对象 `The error should make it clear to you that you need to convert the`整数。
|
|||
|
|
|||
|
```py
|
|||
|
age = "18"
|
|||
|
age_int = int(age)
|
|||
|
print(age_int+2)
|
|||
|
```
|
|||
|
|
|||
|
输出:
|
|||
|
|
|||
|
```py
|
|||
|
20
|
|||
|
```
|
|||
|
|
|||
|
但是你应该记住一些特殊情况:
|
|||
|
|
|||
|
1. 浮点(带小数部分的整数)作为参数将返回向下舍入到最接近的整数的浮点数。 例如: `print(int(7.9))`将打印`7` 。 `print(int("7.9"))`也会导致错误,因为字符串是转换为整数的无效参数。
|
|||
|
|
|||
|
```py
|
|||
|
Traceback (most recent call last):
|
|||
|
File "<stdin>", line 1, in <module>
|
|||
|
ValueError: invalid literal for int() with base 10: '7.9'
|
|||
|
|
|||
|
```
|
|||
|
|
|||
|
2. 如果作为参数给出,任何单词中的任何整数都将返回与上面相同的错误: `print(int("one"))`将给出如下错误:
|
|||
|
|
|||
|
```py
|
|||
|
Traceback (most recent call last):
|
|||
|
File "<stdin>", line 1, in <module>
|
|||
|
ValueError: invalid literal for int() with base 10: 'one'
|
|||
|
|
|||
|
```
|
|||
|
|
|||
|
|
|||
|
#### 更多信息:
|
|||
|
|
|||
|
可在[此处](https://docs.python.org/3.6/library/functions.html#int)找到`int()`内置的官方文档
|