Quick Introduction to Python Programming: 19 Essential Syntax Elements

Many people hear that Python is easy to learn, has good prospects, and high salaries, so they want a fast way to get started; this guide presents the first step: 19 essential Python syntax topics.

Python Features : interpreted language, interactive shell, object‑oriented, cross‑platform, simple yet powerful.

01 Encoding : Use UTF‑8 to avoid garbled characters; add

#!/usr/bin/env python
# coding:utf8

at the top of scripts.

02 Variables : Containers for values; names may contain letters, digits, underscores (not starting with a digit) and are case‑sensitive; Python is weakly typed. Types include numbers, strings, lists, tuples, dictionaries.

03 Numbers : Integers and floats. Example:

# integer
a = 1
# float
b = 2.1
print a, b

04 Strings : Enclosed in single or double quotes; can concatenate with +, get length with len(), slice with [start:stop]. Example:

c = "Hello"
d = "你好"
print c + d
print len(c)
print c[0]
print c[1:5]

05 Lists : Ordered collections, defined with [], mutable. Example:

a = []
a.append(1)
a.append(2.1)
a.append("Hello")
print a
print len(a)
print a[1], a[-1]
a[1] = 100
print a
del a[0]
print a

06 Tuples : Immutable ordered collections, defined with (). Example:

a = (1, 2.1, "Hello")
# a[0] = 100  # raises error

07 Dictionaries : Key‑value mappings, defined with {}. Example:

a = {}
a["k1"] = 1
a["k2"] = 2.1
a["k3"] = "Hello"
print a.has_key("k4")  # returns False

08 Comments : Use # for single‑line comments; multi‑line comments can be created by repeating #.

09 Reserved Words : Avoid using Python keywords (e.g., import, class) as identifiers.

10 Indentation : Code blocks are defined by consistent indentation rather than braces.

11 Operators : Arithmetic (+, -, *, /, %), comparison (==, !=, >, <, >=, <=), assignment (=, +=, etc.), logical (and, or, not). Example:

a = 1
b = 2
print a + b
print a == b
c = True
d = False
print c and d

12 Conditionals : Use if, elif, else with proper indentation. Example:

a = 1
if a == 1:
    print "11111"
elif a == 2:
    print "22222"
else:
    print "33333"

13 Loops : Perform repetitive tasks.

14 while Loop : Executes while a condition is true; remember to modify the loop variable. Example:

flag = 1
while flag < 10:
    print flag
    flag += 1

15 for Loop : Iterate over a range, list, or dictionary. Example:

for x in xrange(0, 10):
    print x

li = [1, 2.1, "Hello"]
for item in li:
    print item
for key in dict.keys():
    print key
for key, value in dict.items():
    print key, value

16 Loop Control : pass (do nothing), continue (skip to next iteration), break (exit loop). Example:

for x in xrange(0, 10):
    if x == 5:
        pass
    else:
        print x

17 Time : Unix timestamp represents seconds since 1970‑01‑01. Convert between timestamp and readable time using time.time(), time.mktime(), time.strftime(), time.strptime(). Example:

import time
t = time.time()
print t, type(t)

18 File I/O : Open files with open() in write ( w) or append ( a) mode, write strings, read lines, and close files. Example:

fw = open('data.txt', 'w')
for x in xrange(0, 10):
    fw.write(str(x))
fw.close()
fr = open('data.txt', 'r')
for line in fr:
    print line.strip()
fr.close()

19 Exceptions : Handle predictable errors with try, except, else, finally. Example:

try:
    print 1 / 0
except Exception as e:
    print e
else:
    print "No error"
finally:
    print "Always runs"

20 Functions : Define reusable code blocks with def, call them with arguments. Example:

def hello(name1, name2):
    print "Hello " + name1 + " and " + name2

hello("Python", "JavaScript")

Thank you for reading; this concludes the first step—19 essential Python syntax elements—for quickly getting started with Python programming.