Python determines whether a string is a letter or a number

Strict parsing: There are symbols except numbers or letters (spaces, semicolons, etc) will be false
Isalnum () must be a mix of numbers and letters
Isalpha () is case insensitive

str_1 ="123"str_2="ABC"str_3="123ABC"#Use the IsDigit function to determine whether a numberPrint(Str_1.isdigit ()) TurePrint(Str_2.isdigit ()) FalsePrint(Str_3.isdigit ()) False#use Isalpha to determine if the letterPrint(Str_1.isalpha ()) FalsePrint(Str_2.isalpha ()) TurePrint(Str_3.isalpha ()) False#Isalnum judge whether a combination of numbers and lettersPrint(Str_1.isalpha ()) FalsePrint(Str_2.isalpha ()) FalsePrint(Str_1.isalpha ()) Ture

Python determines whether a string is a letter or a number