add Python string

README.md

@@ -49,6 +49,7 @@ A data structure is a data organization, management, and storage format that is
 <tr>
 <td>String</td>
 <td>
+<a href="/concepts/python/string.md"><code>py🐍</code></a>
 </td>
 </tr>
 <tr>

concepts/python/string.md

@@ -0,0 +1,86 @@
+# String
+
+From wikipedia
+
+> In computer programming, a string is traditionally a sequence of characters, either as a literal constant or as some kind of variable. The latter may allow its elements to be mutated and the length changed, or it may be fixed (after creation).
+
+## 💻 String Implementation in Python
+
+```python
+# Creating a string
+str_1 = "This is a sample string"
+print(str_1)                   # This is a sample string
+str_1 = "This is " + "a sample string"
+print(str_1)                   # This is a sample string
+
+# Lenght of string
+print(len(str_1))              # 23
+
+# Accessing charactors of string
+print(str_1[0])                # T
+print(str_1[-1])               # g
+
+# Reversing a string
+print(str_1[::-1])             # gnirts elpmas a si sihT
+
+# Slicing a string
+print(str_1[10:-6])            # sample
+
+# String formatting
+
+# Default order
+str_1 = "{} {} {}".format('Zero', 'One', 'Two')
+print(str_1)                   # Zero One Two
+# Positional Formatting
+str_2 = "{1} {0} {2}".format('Zero', 'One', 'Two')
+print(str_2)                   # One Zero Two
+# Keyword Formatting
+str_3 = "{l} {f} {g}".format(g='Zero', f='One', l='Two')
+print(str_3)                   # Two One Zero
+
+# Formatting of Integers
+str_4 = "{0:b}".format(16)     
+print(str_4)                   # 10000
+ # Formatting of Floats
+str_5 = "{0:e}".format(165.6458)
+print(str_5)                   # 1.656458e+02
+# Rounding off Integers
+str_6 = "{0:.2f}".format(1/6)
+print(str_6)                   # 0.17
+
+# Formatted string literals
+value = 2.791514
+print(f'{value:.2f}')          # 2.79
+car = {'tires':4, 'doors':2}
+print(f'car = {car}')          # car = {'tires': 4, 'doors': 2}
+
+# String %
+text = "%d little pigs come out, or I'll %s, and I'll %s, and I'll blow your %s down." % (3, 'huff', 'puff', 'house')
+print(text)                    # 3 little pigs come out, or I'll huff, and I'll puff, and I'll blow your house down.
+
+# String Methods
+
+s = " Hanoi is the capital of Vietnam "
+print(s.lower())               #  hanoi is the capital of vietnam
+print(s.upper())               #  HANOI IS THE CAPITAL OF VIETNAM
+print(s.strip())               # Hanoi is the capital of Vietnam
+print(s.isalpha())             # False
+print(s.isdigit())             # False
+print(s.isspace())             # False
+print(s.startswith(' Hanoi'))  # True
+print(s.endswith('other'))     # False
+print(s.find('Viet'))          # 25
+print(s.replace('the capital', 'a city'))  #  Hanoi is a city of Vietnam
+list_1 = s.split(' ')          
+print(list_1)                  # ['', 'Hanoi', 'is', 'the', 'capital', 'of', 'Vietnam', ''] 
+print(' '.join(list_1))        #  Hanoi is the capital of Vietnam
+```
+
+
+## 🔗 Further Reading
+
+* [Python String](https://docs.python.org/3/library/string.html), docs.python.org
+* [Python Strings](https://developers.google.com/edu/python/strings), developers.google.com
+* [Python String](https://www.geeksforgeeks.org/python-string/), geeksforgeeks.org 2023
+* ▶️ [How to Use Strings in Python](https://www.youtube.com/watch?v=Ctqi5Y4X-jA), Programming with Mosh
+