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Update README.md

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Signed-off-by: David Rotermund <54365609+davrot@users.noreply.github.com>
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@ -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[3:]) # -> ['DD', 'EE', 'FF', 'GG', 'HH']
print(collection_of_strings[1:-1]) # -> ['BB', 'CC', 'DD', 'EE', 'FF', 'GG'] print(collection_of_strings[1:-1]) # -> ['BB', 'CC', 'DD', 'EE', 'FF', 'GG']
print(collection_of_strings[-3:]) # -> ['FF', 'GG', 'HH'] 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 ## Changing lists
@ -112,6 +116,8 @@ collection_of_strings[:4] = [
print(collection_of_strings) # -> ['MM', 'NN', 'OO', 'PP', 'EE', 'FF', 'GG', 'HH'] print(collection_of_strings) # -> ['MM', 'NN', 'OO', 'PP', 'EE', 'FF', 'GG', 'HH']
``` ```
## List functions ## List functions
### [len()](https://docs.python.org/3/library/functions.html#len) and [sorted()](https://docs.python.org/3/library/functions.html#sorted) ### [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'] 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 ```python
primes = [2, 3, 5, 7] primes = [2, 3, 5, 7]
print(sum(primes)) # -> 17 print(sum(primes)) # -> 17
print(max(primes)) # -> 7 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) ### [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 ```python
@ -176,26 +249,10 @@ collection_of_strings.remove("BB")
print(collection_of_strings) # -> ValueError: list.remove(x): x not in list 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) ## [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 ```python
collection_of_strings = [] collection_of_strings = []
collection_of_strings.append("BB") collection_of_strings.append("BB")
@ -210,27 +267,12 @@ del collection_of_strings[1]
print(collection_of_strings) # -> ['AA', 'CC', 'DD'] 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 ```python
collection_of_strings_a = [ collection_of_strings_a = [
"AA", "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'] 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) ## [Additional commands](https://docs.python.org/3/tutorial/datastructures.html)
|| ||