1. `find()` 方法
s = "Hello World"
index = s.find("World")
print(index) 输出:6
2. `index()` 方法
s = "Hello World"
index = s.index("World")
print(index) 输出:6
3. `rfind()` 方法
s = "Hello World"
index = s.rfind("World")
print(index) 输出:6
4. `rindex()` 方法
s = "Hello World"
index = s.rindex("World")
print(index) 输出:6
5. `in` 关键字
s = "Hello World"
if "World" in s:
print("World found in the string")
6. `str.contains` 方法(Pandas Series)
import pandas as pd
s = pd.Series(["Hello World"])
indices = s[s.str.contains("World")].index
print(indices) 输出:0
7. `str.eq` 方法(Pandas Series)
import pandas as pd
s = pd.Series(["Hello World"])
indices = s[s.str.eq("World")].index
print(indices) 输出:0