Python: String Operations

By Xah Lee. Date: . Last updated: .

Substring

Substring extraction is done by appending [begin_index:end_index].

#-*- coding: utf-8 -*-
# python

aa = "01234567"
print aa[2:4] # prints “23”. Does not include the end.

# negative index counts from end, starting with -1
bb = "this"
print bb[0:-2] # prints “th”

# when first index is omitted, default to 0.
# when second index is omitted, default to -1.
cc = "that"
print cc[:] # prints “that”

String Length

Length of the string is len().

#-*- coding: utf-8 -*-
# python

a="this"
print len(a) # 4

String Join and Repetition

Strings can be joined by a plus sign +.

#-*- coding: utf-8 -*-
# python

print "this" + " that"

String can be repeated using *.

#-*- coding: utf-8 -*-
# python

print "this" * 2

Python String

  1. Quote String
  2. String Operations
  3. String Methods
  4. Format String

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Python by Example

  1. Python Basics
  2. Print Version String
  3. Builtin Help
  4. Quote String
  5. String Operations
  6. String Methods
  7. Format String
  8. True, False
  9. if then else
  10. for, while, Loops
  11. List Basics
  12. Loop Thru List
  13. Map Function to List
  14. List Comprehension
  15. List Methods
  16. Dictionary
  17. Loop Thru Dict
  18. Dict Methods
  19. Function
  20. Class
  21. List Modules
  22. Write a Module
  23. Unicode 🐍

Regex

  1. Regex Basics
  2. Regex Reference

Text Processing

  1. Read/Write File
  2. Traverse Directory
  3. Manipulate Path
  4. Process Unicode
  5. Convert File Encoding
  6. Find Replace in dir
  7. Find Replace by Regex
  8. Count Word Frequency

Web

  1. Send Email
  2. GET Web Page
  3. Web Crawler
  4. HTTP POST
  5. Check Page Load Size
  6. Thumbnail Generation

Misc

  1. JSON
  2. Find Script Path
  3. Get Env Var
  4. System Call
  5. Decompress Gzip
  6. Complex Numbers

Advanced

  1. Sort
  2. Copy Nested List
  3. Tuple vs List
  4. Sets, Union, Intersection
  5. Closure in Python 2
  6. Decorator
  7. Append String in Loop
  8. Timing f timeit
  9. Keyword Arg Default Value Unstable