Lists in Python

In Python, list slicing lets you extract portions of a list using the syntax:

list[start:stop:step]

Components

• start → index where the slice begins (inclusive).

• stop → index where the slice ends (exclusive).

• step → interval between indices (default is 1).

numbers = [10, 20, 30, 40, 50, 60] print(numbers[1:4]) # [20, 30, 40] (from index 1 to 3) print(numbers[:3]) # [10, 20, 30] (first 3 elements) print(numbers[3:]) # [40, 50, 60] (from index 3 to end) print(numbers[::2]) # [10, 30, 50] (every 2nd element) print(numbers[::-1]) # [60, 50, 40, 30, 20, 10] (reversed list)

numbers[1:4]

• Start = 1 → begin at index 1 (the second element, which is 20).

• Stop = 4 → go up to, but not including, index 4.

• So you get elements at indices 1, 2, and 3 → 20, 30, 40.

Python slicing always excludes the stop index. That’s why 50 (at index 4) isn’t included.

print(numbers[::2])

• Start = empty → defaults to the beginning of the list (index 0).

• Stop = empty → defaults to the end of the list.

• Step = 2 → take every second element.

So Python picks indices 0, 2, 4, ... until the end

myList = [1, 2, 3, 4, 5] print(myList[0:6:2])

Start = 0 → begin at index 0 (1).

Stop = 6 → go up to, but not including, index 6.

Step = 2 → take every second element.

Notice that even though you wrote stop = 6, your list only goes up to index 4. Python slicing doesn’t throw an error — it just stops at the end of the list. That’s why you still get [1, 3, 5].

The range() function in Python generates a sequence of integers, starting from a given start (default 0), stopping before a given stop, and incrementing by a given step (default 1). It’s most often used in loops to control iteration.

range(start, stop, step)

start → optional, default 0. First number in the sequence.

stop → required. Sequence ends before this number.

step → optional, default 1. Difference between consecutive numbers.

Range function is immutable.

>>> for i in range(5): ...     print(i) ... 0 1 2 3 4 >>>

>>> myList = [1,2,3,4] ... myList.append(5) ... print(myList) ... [1, 2, 3, 4, 5] >>>

In Python, lists have several useful methods for adding and removing elements. Let’s look at insert(), remove(), and pop() side by side:

numbers = [10, 20, 30] numbers.insert(1, 15) # insert 15 at index 1 print(numbers) # [10, 15, 20, 30]

numbers = [10, 20, 30, 20] numbers.remove(20) # removes the first 20 print(numbers) # [10, 30, 20]

pop(): remove and return an element at a given index (default is the last element).

>>> myList = [1,2,3,4,5]

>>> myList.pop()

5

numbers = [10, 20, 30] x = numbers.pop(1) # removes element at index 1 print(x) # 20 print(numbers) # [10, 30]

>>> myList = [1,2,3,4,5]

... while len(myList):

...     print(myList.pop())

...

5

4

3

2

1

Loop ends because len(myList) is now 0.

>>> a = [1,2,3,4,5]

... b = a.copy()

... a.append(6)

... print(a)

... print(b)

...

[1, 2, 3, 4, 5, 6]

[1, 2, 3, 4, 5]

b = a.copy() → makes a shallow copy of a.

• Now b has its own separate list [1,2,3,4,5].

Microsoft Copilot

White Balance

Auto (White Priority): best for indoor fluorescent or mixed light

Shade: adds warmth to counter bluish tones

Cloudy: warmer balance, good for HK’s cloudy spring weather

Tungsten Light: best for indoor with incandescent bulbs

White Fluorescent Light: best for offices, malls in HK

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Personal Computer

Albuquerque: city (the state's most populous) in central New Mexico population 545,852

makeshift: used temporarily for a particular purpose because the real thing is not available

plywood: board made by sticking thin layers of wood on top of each other

The Altair 8800, introduced by MITS in January 1975, is widely recognized as the first commercially successful personal computer, igniting the microcomputer revolution.

laundromat: ​​a place where you can wash and dry your clothes in machines that you pay to use

massage parlor: a place where you can pay to have a massage

shell out: ​(informal) to pay a lot of money for something

novelty: the quality of being new, different and interesting

splurge: an act of spending a lot of money on something that you do not really need

gadget: a small tool or device that does something useful

tinker: tinker (with something) to make small changes to something in order to repair or improve it, especially in a way that may not be helpful

Menlo Park: city in western California southeast of San Francisco population 32,026

swap: to give something to somebody and receive something in exchange

glimpse: a sight of somebody/something for a very short time, when you do not see the person or thing completely

toggle: to press a key or set of keys on a computer keyboard in order to turn a feature on or off, or to move from one program, etc. to another

staccato: (music, from Italian) with each note played separately in order to produce short, sharp sounds

rendition: the performance of something, especially a song or piece of music; the particular way in which it is performed

2001: A Space Odyssey is a seminal 1968 science fiction film directed by Stanley Kubrick and co-written with Arthur C. Clarke.

home brew: beer that somebody makes at home

stoke something (up) to make something increase or develop more quickly

whistle-stop: visiting a lot of different places in a very short time

counterculture: a way of life and set of ideas that are opposed to those accepted by most of society; a group of people who share such a way of life and such ideas

hippie: a person who rejects the way that most people live in Western society, often having long hair, wearing brightly colored clothes and taking illegal drugs. The hippie movement was most popular in the 1960s.

zeitgeist: the general mood or quality of a particular period of history, as shown by the ideas, beliefs, etc. common at the time

monolithic: ​(often disapproving) used to describe single, very large organizations that are very slow to change and not interested in individual people

Lockheed Martin (NYSE: LMT) is the world's largest defense and aerospace corporation

inaugural: IPA[ɪˈnɔːgjʊrəl]

Bill Gates "Source Code"

Online Dictionaries Used:

hk.dictionary.search.yahoo.com

www.oxfordlearnersdictionaries.com

www.merriam-webster.com

Google AI Overview

Testing New Al Alloy Tripod

Mode: Manual

ISO 400, 35mm(APS-C), f/5.6, 1/40s

Flash: compulsory; Tripod Used, Image Stabilization of Lens Off 

Flash Exposure Compensation is lowered.

Two-second Self-Timer set

    When using a tripod with the Canon EOS 1500D and EF-S 18-135mm f/3.5-5.6 IS USM lens, I have the advantage of stability, which allows me to use slower shutter speed to capture more ambient light while using the flash to fill in the subject.

    Since I don't have bounce flash, I use direct flash. This is more powerful but can create harsh shadows and "flat" lighting. Since I have a tripod, I can use it to manage the quality of image while dealing with the harsh direct light.

    Flash Exposure Compensation (FEC): Direct flash often looks "too bright" or creates unnatural highlights. Go into the camera's flash menu and lower the FEC to -1 or -2. This softens the effect, making the flash look like a subtle "fill" light rather than a harsh strobe.

    Balance with ambient light: Since I have a tripod, I don't have to rely on the flash only. Use a slower shutter speed (e.g. 1/30 or 1/40s) to allow room light to contribute to the exposure.

    Recommended Setting

Mode: Manual

Allows me to keep settings consistent.

Shutter Speed: 1/40s - 1/60s

Slow enough to pull in background light.

Aperture: f/4 - f/5.6

Keeps a good balance between light intake and sharpness.

ISO: ISO 400-800

Keeps the image clean while ensuring the flash doesn't have to work at full power.

Flash Power: -1 or -2 FEC

Prevents the subject from looking "blown out" or too harsh.

    Image stabilization is often turned off on a tripod because the stabilizer is designed to look for movement and correct it; when the camera is already perfectly still, some systems can "hunt" or make tiny corrections that create blur instead of reducing it.

Information from Perplexity.ai and edited

善用曝光補償

例子︰夜景

相機測光認為是太暗，用光圈先決的話，相機會自動調光一些。這個時候，曝光補償的設定取決於拍攝意圖。

例子︰雪景

相機測光認為是太亮，用光圈先決的話，相機會自動調暗一些。這個時候要將曝光補償設定成 +1~1.5EV。

Python Quiz

In Python, int(9.9) returns 9.

Here’s why:

The int() function truncates the decimal part of a floating-point number.

It does not round — it simply drops everything after the decimal point.

So 9.9 becomes 9.

In Python, any nonzero number (whether int, float, or complex) evaluates to True when converted to bool.

In Python, int and Decimal are both numeric types, but they serve very different purposes: int is for whole numbers, while Decimal is for precise decimal arithmetic, often used in finance or scientific contexts.

When you run bytes(4) in Python, it creates a bytes object of length 4, filled with zeros.

b = bytes(4)

print(b)   # b'\x00\x00\x00\x00'

bytes(n) → produces a sequence of n bytes.

Each byte is initialized to 0 (\x00 in hexadecimal).

The result is immutable, meaning you cannot change its contents after creation.

b = bytes(5)

print(b)   # b'\x00\x00\x00\x00\x00'

In Python, writing with triple quotes (''' ... ''' or """ ... """) creates a multi‑line string.

Microsoft Copilot

微距拍攝

    在微距拍攝中通常不需要使用大光圈，因為即使在中小光圈下，景深已經非常淺。在 1:1 放大倍率下，即使使用 f/8–f/11，景深也只有幾毫米。若用大光圈 (f/2.8–f/4)，景深可能縮到不到 1 毫米，導致昆蟲的眼睛清晰但觸角完全模糊。大光圈下焦點範圍極窄，任何微小晃動或主體移動都會失焦。若使用小光圈 (如 f/16)，光線較少，需要額外補光或使用閃燈。這也是為什麼常見的工作光圈範圍在 f/8–f/11。

    標準鏡頭即使靠近拍攝，放大倍率通常不足 1:1，景深相對較深，因此不需要像微距那樣擔心「極淺景深」。在標準鏡頭特寫中，使用大光圈 (f/1.8–f/2.8) 仍能創造淺景深效果，讓背景柔和模糊。但因為放大倍率不高，景深不會像微距那樣縮到幾乎不可用，焦點範圍仍有一定寬度。

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