python字符串find_Python字符串| 带示例的find（）方法

淩亂°似流年 2023-03-05 15:51 89阅读 0赞

python字符串find

## String.find()方法 **(**String.find() Method**)** ##

find() is an inbuilt method of python, it is used to check whether a sub-string exists in the string or not. If sub-string exists, the method returns the lowest index of the sub-string, if sub-string does not exist, method return -1.

find()是python的内置方法，用于检查字符串中是否存在子字符串。 如果存在子字符串，则该方法返回子字符串的最低索引，如果子字符串不存在，则方法返回-1。

**Note:** This method is case sensitive.

**注意：**此方法区分大小写。

**Syntax:**

**句法：**

String.find(sub_string[, start_index[, end_index]])

**Parameters:**

**参数：**

*  sub\_string \- a part of the string to be found in the string.
    
    sub\_string-要在字符串中找到的字符串的一部分。
 *  start\_index \- an optional parameter, it defines the starting index from where sub\_string should be found.
    
    start\_index-可选参数，它定义从中应找到sub\_string的起始索引。
 *  end\_index \- an optional parameter, it defines end index of the string. Find method will find the sub\_string till this end\_index.
    
    end\_index-可选参数，它定义字符串的结束索引。 Find方法将查找sub\_string直到此end\_index 。

**Return value:**

**返回值：**

*  **Returns the lowest index** of the sub\_string, if it exits in the string.
    
    **返回** sub\_string **的最低索引** ，如果它存在于字符串中。
 *  **Returns -1** if sub\_string does not exist in the string.
    
    如果sub\_string在字符串中不存在，则**返回-1** 。

**Example:**

**例：**

# string in which we have to find the sub_string
    str = "Hello world, how are you?"
    
    # sub_string to find the given string 
    sub_str = "how"
    
    # find by sub_str
    print (str.find (sub_str))
    
    # find by sub_str with slice:start index
    print (str.find (sub_str, 10))
    
    # find by sub_str with slice:start index and slice: end index
    print (str.find (sub_str, 10, 24))
    
    # find a sub_str that does not exist
    sub_str = "friend"
    # find by sub_str
    print (str.find (sub_str))
    
    # find a sub_str with different case 
    sub_str = "HOW"
    # find by sub_str
    print (str.find (sub_str))

**Output**

**输出量**

13
        13
        13
        -1
        -1

> 翻译自: [https://www.includehelp.com/python/string-find-method-with-example.aspx][https_www.includehelp.com_python_string-find-method-with-example.aspx]

python字符串find

[https_www.includehelp.com_python_string-find-method-with-example.aspx]: https://www.includehelp.com/python/string-find-method-with-example.aspx