字符串转换整数python

Unlike many other programming languages out there, Python does not implicitly typecast integers (or floats) to strings when you concatenate them to strings.

与现有的许多其他编程语言不同，Python在将整数连接到字符串时不会隐式地将整数(或浮点数)类型转换为字符串。

Fortunately, Python has a handy built-in function str() which will convert the argument passed in to a string format.

幸运的是，Python有一个方便的内置函数str() ，它将把传入的参数转换为字符串格式。

在Python中将字符串转换为整数的错误方法 (The Wrong Way to Convert a String to an Integer in Python)

Programmers coming from other programming languages may attempt to do the following string concatenation, which will produce an error:

来自其他编程语言的程序员可能会尝试执行以下字符串连接，这将产生错误：

age = 18

string = "Hello, I am " + age + " years old"

You can run this code on repl.it.

您可以在repl.it上运行此代码 。

The error that shows up is:

显示的错误是：

Traceback (most recent call last):
  File "python", line 3, in <module>
TypeError: must be str, not int

Here, TypeError: must be str, not int indicates that the integer must first be converted to a string before it can be concatenated.

在这里， TypeError: must be str, not int ，该整数必须先转换为字符串才能连接。

在Python中将字符串转换为整数的正确方法 (The Correct Way to Convert a String to an Integer in Python )

Here's a simple concatenation example:

这是一个简单的串联示例：

age = 18

print("Hello, I am " + str(age) + " years old")

# Output
# Hello, I am 18 years old

You can run this code on repl.it.

您可以在repl.it上运行此代码 。

Here's how to print 1 2 3 4 5 6 7 8 9 10 using a single string:

以下是使用单个字符串打印1 2 3 4 5 6 7 8 9 10方法：

result = ""

for i in range(1, 11):
    result += str(i) + " "

print(result)

# Output
# 1 2 3 4 5 6 7 8 9 10

You can run the code on repl.it.

您可以在repl.it上运行代码 。

以下是上述代码的工作原理的逐行说明： (Here's a line-by-Line explanation of how the above code works:)

1. First of all a variable ‘result’ is assigned to an empty string.
   首先，将变量“结果”分配给一个空字符串。
2. The for loop is being used to iterate over a list of numbers.
   for循环用于遍历数字列表。
3. This list of numbers is generated using the range function.
   此数字列表是使用范围函数生成的。
4. so range(1,11) is going to generate a list of numbers from 1 to 10.
   因此range(1,11)将生成一个从1到10的数字列表。
5. On each for loop iteration this ‘i’ variable is going to take up values from 1 to 10.
   在每个for循环迭代中，此“ i”变量将采用从1到10的值。
6. On first iteration when the variable i=1,then the variable [result=result+str(i)+“(space character)”],str(i) converts the ‘i’ which is an integer value to a string value.
   在第一次迭代中，当变量i = 1时，然后变量[result = result + str(i)+“(space character)”]，str(i)将整数值“ i”转换为字符串值。
7. Since i=1, on the first iteration finally result=1.
   由于i = 1，因此在第一次迭代中最终结果= 1。
8. And the same process goes on until i=10 and finally after the last iteration result=1 2 3 4 5 6 7 8 9 10.
   直到i = 10，最后一次迭代结果= 1 2 3 4 5 6 7 8 9 10。
9. Therefore when we finally print the result after the for loop the output on the console is ‘1 2 3 4 5 6 7 8 9 10’.
   因此，当我们最终在for循环之后打印结果时，控制台上的输出为'1 2 3 4 5 6 7 8 9 10'。

I hope you've found this helpful. Happy coding.

希望对您有所帮助。 快乐的编码。

翻译自: https://www.freecodecamp.org/news/python-string-to-int-how-to-convert-a-string-to-an-integer-in-python/

字符串转换整数python