Python String startswith()用法及代码示例

如果字符串以给定前缀开头，则startswith()方法返回True，否则返回False。

用法:

str.startswith(prefix, start, end)

参数：

prefix : prefix ix nothing but a string which needs to be checked.
start : Starting position where prefix is needs to be checked within the string.
end : Ending position where prefix is needs to be checked within the string.

注意：如果未提供开始索引和结束索引，则默认情况下它将0和length-1用作开始索引和结束索引，而我们的搜索中不包含结束索引。

返回值：

It returns True if strings starts with the given
prefix otherwise returns False.

例子：

Input : text = "geeks for geeks."
        result = text.startswith('for geeks')
Output : False

Input : text = "geeks for geeks."
        result = text.startswith('geeks', 0)
Output : True

错误：ValueError：在目标字符串中未找到参数字符串的情况下，会引发此错误

# Python code shows the working of 
# .startsswith() function 
   
text = "geeks for geeks."
   
# returns False 
result = text.startswith('for geeks') 
print (result) 
   
# returns True 
result = text.startswith('geeks') 
print (result) 
   
# returns False 
result = text.startswith('for geeks.') 
print (result) 
   
# returns True 
result = text.startswith('geeks for geeks.') 
print (result)

输出：

False
True
False
True