1. count() 計算”目標”出現 幾次

string1 = " Today is a good day "
string2 = "Good day is a good day"
print(string1.count("good"))
print(string2.lower().count("good"))  # 先lowercase 再counting
-----------------------------------

[Running] python -u "d:\\2022_python_全攻略\\18. find, count, startswith, endswith"
1
2

Index 和find 區別

1. index 會return exception ; find return -1
2. 如果你不確定substrate 能不能被找到 用find / 而不用index
3. find 只能用在string 資料類型 ; index 可以用在其它資料類型 tuple / list

startswith() / endswith()

1. 確認起始字和末端字

# count

string1 = " Today is a good day "
string2 = "Good day is a good day"
print(string1.count("good"))
print(string2.lower().count("good"))  # 先lowercase 再counting

output----------------------------------------------

[Running] python -u "d:\\2022_python_全攻略\\18. find, count, startswith, endswith"
1
2

----------------------------------------------

# find method 跟 Index 類似

string1 = " Today is a good day "
print(string1.find("day"))
print(string1.index("day"))

# startswith /endswith
name = "Albert_Chen"
print(name.startswith("A"))
print(name.endswith("Chen"))

output------------------------------------
[Running] python -u "d:\\2022_python_全攻略\\18. find, count, startswith, endswith"
3
3
True
True