Python Basic introduction （ A full set of nanny level tutorials ）

Chapter two

Section 5 ： Find and judge

**find：** Output returns if -1 The string does not appear .
index： If you report an error, there is no .
in You can make conditional judgments ,not in Determine whether there is no .

s = " How do you do .  My name is Chow Yun fat "
ret = s.find(" Chow yun-fat 12312")  #  Return if yes -1 The string does not appear 
print(ret)
ret = s.index(" Chow yun-fat 12312")  #  If you report an error, there is no 
print(ret)

print(" Chow yun-fat " in s)  # in You can make conditional judgments 
print(" Chow yun-fat " not in s)  # not in  Determine whether there is no 

**startswith：** Determine whether the string is based on xxxxx start , endswith() And startswith contrary , Try it yourself .
**isdigit：** Determine whether the string consists of integers .

name = input(" Please enter your name :")
#  Judge whether your surname is Zhang 
if name.startswith(" Zhang "):  #  Determine whether the string is based on xxxxx start , endswith()
    print(" Your name is Zhang ")
else:
    print(" No, Zhang ")

money = input(" Please enter your money :")

if money.isdigit():  #  Determine whether the string consists of integers .
    money = int(money)
    print(" You can spend money ")
else:
    print(" I'm sorry , Your input is wrong ....")

summary ：

Remember these startswith(), isdigit(), in, not in, find.