radytrainer/python-syntax-note

Python basic syntax note

1. Variable

• number = 0 // integer variable
• text = "Hello, world!" // string variable
• hasNumber = True // boolean variable
• average = 12.3 // float variable

2. Conditional expression

• if condition

if condition:
    // your code here

# Example
if 5 < 10:
    print("Yes")

• if - else conditions (Work only one block)

if condition:
    // your code here
else:
    // your code here

# Example
if 3 < 4:
    print("Yes")
else:
    print("No")

• if - elif conditions (Work only one block)

if condition:
    // your code here
elif condition:
    // your code here

# Example
if 3 < 4:
    print("Yes")
elif 4 < 3:
    print("No")

• if - elif - elif ... - else conditions (Work only one block)

if condition:
    // your code here
elif condition:
    // your code here
elif condition:
    // your code here
...
else:
    // your code here

# Example
if 3 < 4:
    print("Yes")
elif 4 < 3:
    print("No")
elif 5 < 3:
    print("Okay")
elif 6 < 3:
    print("Sorry")
else:
    print("Goodbye")

• if - if conditions (Work both block if condition is true)

if condition:
    // your code here
if condition:
    // your code here

# Example
if 3 < 4:
    print("Yes")
if 4 < 3:
    print("No")

• Nesting if condition

if condition:
    if condition:
        // your code here
    else:
        // your code here
else:
    if condition:
        // your code here
# Example
if 3 < 4:
    if 3 == 4:
        print("Yes")
    else:
        print("No")
else:
    if 3 < 7:
        print("Okay")

3. Loop

• for loop by default variable in for loop start from 0 and in range must be integer value

for variable in range(integer_value):
    // your code here

# Example
for i in range(3):
    print(i)
# Output
0
1
2

• while loop always secute while condition is true

while condition:
    // your code here

# Example
i = 0
while i < 3:
    print(i)
    i = i + 1
# Output
0
1
2

4. String function allow to use in algorithm course

• len() returns number of characters

print(len("hello"))
# output
5

• str() returns string

print(str(100))
#output
"100"

• upper() returns string with uppercase characters

text = "Hello".upper()
print(text)
# output
HELLO

• lower() returns string with lowercase characters

text = "HELLO".lower()
print(text)
# output
hello

• isupper() returns True if string is uppercase otherwise False

hasUpper1 = "A".isupper()
hasUpper2 = "b".isupper()
print(hasUpper1)
print(hasUpper2)
# output
True
False

• islower() returns True if string is lowercase otherwise False

hasLower1 = "A".islower()
hasLower2 = "b".islower()
print(hasLower1)
print(hasLower2)
# output
False
True

• isnumeric() returns True if string is type of integer otherwise False

hasNumber1 = "A".isnumeric()
hasNumber2 = "3".isnumeric()
print(hasNumber1)
print(hasNumber2)
# output
False
True