如何使用python搜索字符串中的特定文本

string = "This is a sample string"
if "sample" in string:
    print("特定文本在字符串中")
else:
    print("特定文本不在字符串中")

string = "This is a sample string"
index = string.find("sample")
if index != -1:
    print("特定文本在字符串中，位置为", index)
else:
    print("特定文本不在字符串中")

import re
string = "This is a sample string"
pattern = r"sample"
match = re.search(pattern, string)
if match:
    print("特定文本在字符串中，位置为", match.start(), "-", match.end())
else:
    print("特定文本不在字符串中")