Typical import:

`import something`

or

`from somemodule import somefunction`

or

`from somemodule import somefunction, anotherfunction`

or

`from somemodule import *`

or

`from somemodule import somefunction as different_name`

False:

`False None 0 "" () [] {}`

True:

`True 1 "Some string" (1, 2) [1, 2] {1: 'One'}`

Most common decision construction is *if-elif-else*.

```
if condition1:
body1
elif condition2:
body2
elif condifion3:
body3
.
.
.
elif condition(n-1)
body(n-1)
else:
body(n)
```

Examples:

```
num = int(input('Enter a number: '))
if num > 0:
print('The number is positive')
elif num < 0:
print('The number is negative')
else:
print('The number is zero')
```

Example with pass:

```
if x < 5:
pass
elif x > 5:
pass
else:
x = 5
```

Nested block example:

```
name = input('What is your name? ')
if name.endswith('Gumby'):
if name.startswith('Mr.'):
print('Hello, Mr. Gumby')
elif name.startswith('Mrs.'):
print('Hello, Mrs. Gumby')
else:
print('Hello, Gumby')
else:
print('Hello, stranger')
```

Expression | Description |
---|---|

x == y | x equals y |

x < y | x is less than y |

x > y | x is greater than y |

x >= y | x is greater than or equal to y |

x <= y | x is less than or equal to y |

x != y | x is not equal to y |

x is y | x and y are the same object |

x is not y | x and y are different objects |

x in y | x is a member of the container (e.g., sequence) y |

x not in y | x is not a member of the container (e.g., sequence ) y |

**is: The identity operator**

```
>>> x = y = [1, 2, 3]
>>> z = [1, 2, 3]
>>> x == y
True
>>> x == z
True
>>> x is y
True
>>> x is z
False
```

```
while condition:
body
else: # optional
code continuation
```

Example:

```
x = 1
while x <= 100:
print(x)
x += 1
```

```
for variable in sequence:
body
else: # optional
code continuation
```

Example:

```
numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
for number in numbers:
print(number)
```

Function range can be used in combination with len and for loop like this:

```
>>> x = [1, 2, 3, -7, 5, 10, -5, 4]
>>> for i in range(len(x)):
... if x[i] < 0:
... print("Negative number on index ", i)
...
Negative number on index 3
Negative number on index 6
```

```
>>> range(10)
range(0, 10)
```

The following program writes out the numbers from 1 to 100:

```
for number in range(1,101):
print(number)
```

Iterating over dictionaries:

```
d = {'x': 1, 'y': 2, 'z': 3}
for key, value in d.items():
print(key, 'corresponds to', value)
```

**break**

To end (break out of) a loop, you use break.

```
>>> x = 1
>>>
>>> while True:
... x += 1
... if x == 10:
... break
... else:
... print("Value is ", x)
...
Value is 2
Value is 3
Value is 4
Value is 5
Value is 6
Value is 7
Value is 8
Value is 9
```

**continue**

It causes the current iteration to end and to “jump” to the beginning of the next.

```
>>> x = 1
>>>
>>> while True:
... x += 1
... if x < 10:
... continue
... else:
... print("x has the value ", x)
... break
...
x has the value 10
```

Toto je stránka lekce z kurzu, který probíhá nebo proběhl naživo s instruktorem.