String

```python
user = "1kkjahkdsa"
welcome = f"hello {user}"

print("ajkkk"  in user) # return true/false
#  first_name,last_name,age,region
#ha,do,36,hochiminh city
csv_line = "ha,do,36,true,false,hochiminh city"
data = csv_line.split(",")
print(data[5])
first_name,last_name,*_,region = data # unpacking data
print(f"{first_name} {last_name} live in {region}")

a = 1
b = 5
c = 3
delta = 5 ** 2 - 4*a*c
print("a" in "euoai")

```

```python
csv_line = "ha,do,36,true,false,hochiminh city"
print(csv_line[-5:-1])
```