diff --git a/python_basics/list/README.md b/python_basics/list/README.md index b32df3a..47a4556 100644 --- a/python_basics/list/README.md +++ b/python_basics/list/README.md @@ -83,6 +83,10 @@ print(collection_of_strings[:3]) # -> ['AA', 'BB', 'CC'] print(collection_of_strings[3:]) # -> ['DD', 'EE', 'FF', 'GG', 'HH'] print(collection_of_strings[1:-1]) # -> ['BB', 'CC', 'DD', 'EE', 'FF', 'GG'] print(collection_of_strings[-3:]) # -> ['FF', 'GG', 'HH'] +print(collection_of_strings[0:3]) # -> ['AA', 'BB', 'CC'] +print(collection_of_strings[0:3:1]) # -> ['AA', 'BB', 'CC'] +print(collection_of_strings[0:3:2]) # -> ['AA', 'CC'] +print(collection_of_strings[::2]) # -> ['AA', 'CC', 'EE', 'GG'] ``` ## Changing lists @@ -112,6 +116,8 @@ collection_of_strings[:4] = [ print(collection_of_strings) # -> ['MM', 'NN', 'OO', 'PP', 'EE', 'FF', 'GG', 'HH'] ``` + + ## List functions ### [len()](https://docs.python.org/3/library/functions.html#len) and [sorted()](https://docs.python.org/3/library/functions.html#sorted) @@ -134,14 +140,81 @@ print(len(collection_of_strings)) # -> 8 print(sorted(collection_of_strings)) # -> ['AA', 'BB', 'CC', 'DD', 'EE', 'FF', 'GG', 'HH'] ``` -### [max()](https://docs.python.org/3/library/functions.html#max) and [sum()](https://docs.python.org/3/library/functions.html#sum) +### [max()](https://docs.python.org/3/library/functions.html#max), [min](https://docs.python.org/3/library/functions.html#min) and [sum()](https://docs.python.org/3/library/functions.html#sum) ```python primes = [2, 3, 5, 7] print(sum(primes)) # -> 17 print(max(primes)) # -> 7 +print(min(primes)) # -> 2 ``` + + +## in + +Is **x in list**? + +```python +collection_of_strings = [ + "AA", + "BB", + "CC", + "DD", + "EE", + "FF", + "GG", + "HH", +] +print("AA" in collection_of_strings) # -> True +print("XX" in collection_of_strings) # -> False +print("AA" not in collection_of_strings) # -> False +print("XX" not in collection_of_strings) # -> True +``` + +## [Index](https://docs.python.org/3/tutorial/datastructures.html#more-on-lists) + +Which index id has an element in a list? + +```python +collection_of_strings = [ + "AA", + "BB", + "CC", + "DD", + "EE", + "FF", + "GG", + "HH", +] + +print(collection_of_strings.index("CC")) # -> 2 +print(collection_of_strings.index("XX")) # -> ValueError: 'XX' is not in list +``` + +Maybe we don't want to start in the beginning of the list or don't want to search until the end of the list: + +```python +collection_of_strings = [ + "AA", + "BB", + "CC", + "DD", + "EE", + "BB", + "FF", + "GG", + "BB", + "HH", +] +print(collection_of_strings.index("BB")) # -> 1 +# At or after 2 +print(collection_of_strings.index("BB", 2)) # -> 5 +# Before 6 +print(collection_of_strings.index("BB", 2, 6)) # -> 5 +# Before 4 +print(collection_of_strings.index("BB", 2, 4)) # ValueError: 'BB' is not in list +``` ### [append()](https://docs.python.org/3/tutorial/datastructures.html#more-on-lists), [pop()](https://docs.python.org/3/tutorial/datastructures.html#more-on-lists), and [remove()](https://docs.python.org/3/tutorial/datastructures.html#more-on-lists) ```python @@ -176,26 +249,10 @@ collection_of_strings.remove("BB") print(collection_of_strings) # -> ValueError: list.remove(x): x not in list ``` -## [Index](https://docs.python.org/3/tutorial/datastructures.html#more-on-lists) - -```python -collection_of_strings = [ - "AA", - "BB", - "CC", - "DD", - "EE", - "FF", - "GG", - "HH", -] - -print(collection_of_strings.index("CC")) # -> 2 -print(collection_of_strings.index("XX")) # -> ValueError: 'XX' is not in list -``` - ## [del](https://docs.python.org/3/tutorial/datastructures.html#the-del-statement) and [insert()](https://docs.python.org/3/tutorial/datastructures.html#more-on-lists) +Insert and delete an element. + ```python collection_of_strings = [] collection_of_strings.append("BB") @@ -210,27 +267,12 @@ del collection_of_strings[1] print(collection_of_strings) # -> ['AA', 'CC', 'DD'] ``` -## in -```python -collection_of_strings = [ - "AA", - "BB", - "CC", - "DD", - "EE", - "FF", - "GG", - "HH", -] -print("AA" in collection_of_strings) # -> True -print("XX" in collection_of_strings) # -> False -print("AA" not in collection_of_strings) # -> False -print("XX" not in collection_of_strings) # -> True -``` ## + +Concatenating lists. + ```python collection_of_strings_a = [ "AA", @@ -251,6 +293,43 @@ collection_of_strings = collection_of_strings_a + collection_of_strings_b print(collection_of_strings) # -> ['AA', 'BB', 'CC', 'DD', 'EE', 'FF', 'GG', 'HH'] ``` +## * + +Repeat a list several times. + +```python +collection_of_strings = [ + "AA", + "BB", + "CC", +] +print(3 * collection_of_strings) # -> ['AA', 'BB', 'CC', 'AA', 'BB', 'CC', 'AA', 'BB', 'CC'] +print(collection_of_strings * 3) # -> ['AA', 'BB', 'CC', 'AA', 'BB', 'CC', 'AA', 'BB', 'CC'] +``` + +## count() + +How often does an element occur in the list? + +```python +collection_of_strings = [ + "AA", + "AA", + "BB", + "BB", + "BB", + "CC", + "DD", + "EE", + "FF", + "GG", + "HH", +] +print(collection_of_strings.count("AA")) # -> 2 +print(collection_of_strings.count("BB")) # -> 3 +print(collection_of_strings.count("CC")) # -> 1 +``` + ## [Additional commands](https://docs.python.org/3/tutorial/datastructures.html) ||