Basic Python

  • Print
  • Variables and Types
  • Arithmetic Operations
  • List
  • Dictionary
  • Loop
  • Condition
  • Function
  • Class and Objects

1. Print

Ãâ·ÂÇÔ¼ö

In [1]:
# print ÇÔ¼ö¿¡´Â ±âº»ÀûÀ¸·Î ÁٹٲÞ(new line)ÀÌ µé¾î°¡ ÀÖ½À´Ï´Ù. ±×·¸±â ¶§¹®¿¡ ¿©·¯°³¸¦ Ãâ·ÂÇßÀ»¶§ Ç×»ó ´ÙÀ½ ÁÙ·Î ³Ñ¾î°¡°Ô µË´Ï´Ù.
print("Hello World!") 

# ¹®ÀÚ¿­À» Ãâ·ÂÇÏ°í À̾ Ãâ·ÂÇÒ ¹®ÀÚ¿­À» ¸í½ÃÀûÀ¸·Î ÁöÁ¤ÇÏ´Â ¹æ¹ý. ¿©±â¼­´Â ÁٹٲÞÀ¸·Î ¼³Á¤Çß½À´Ï´Ù.
print("Hello World!",end="\n") 

# ¹®ÀÚ¿­À» Ãâ·ÂÇÏ°í À̾ Ãâ·ÂÇÒ ¹®ÀÚ¿­Àº ¸í½ÃÀûÀ¸·Î ¹Ù²Ü ¼ö ÀÖ½À´Ï´Ù. ¿©±â¼­´Â "end"¶ó´Â ¹®ÀÚ¿­ÀÔ´Ï´Ù.
print("Hello World!",end="end")

Hello World!
Hello World!
Hello World!end
In [2]:
# https://pyformat.info/

# format À̶ó´Â ÇÔ¼ö¸¦ ÀÌ¿ëÇØ ¹®ÀÚ¿­ÀÇ Æ¯Á¤ À§Ä¡¿¡ º¯¼ö¸¦ Ãâ·ÂÇÒ¼öµµ ÀÖ½À´Ï´Ù.
string = "python"
print("I love {}".format(string))

# format ÇÔ¼ö´Â ´Ù¾çÇÑ ¼³Á¤À¸·Î »ç¿ëÇÒ ¼ö ÀÖ½À´Ï´Ù. ¾Æ·¡ÀÇ ¿¹½Ã´Â Àüü 9Ä­¿¡¼­ ¿ÞÂÊ Á¤·Ä, ¿À¸¥ÂÊ Á¤·Ä, °¡¿îµ¥ Á¤·Ä ±×¸®°í ºóÄ­À» ´Ù¸¥ °ªÀ¸·Î ä¿ì´Â ¹æ¹ýÀÔ´Ï´Ù.
print("{:<9}".format(999))
print("{:>9}".format(999))
print("{:^9}".format(999))
print("{:*^9}".format(999))

I love python
999      
      999
   999   
***999***

2. Variables and Types

º¯¼ö¿Í º¯¼öÀÇ Å¸ÀÔ¿¡ °üÇÑ ³»¿ë

In [3]:
# ÆÄÀ̽ãÀº c++ °°Àº ¾ð¾î¿Í ´Þ¸® ŸÀÔÀ» ÁöÁ¤ÇØÁÖÁö ¾Ê°í ÀÚµ¿À¸·Î ŸÀÔÀ» ÁöÁ¤ÇØÁÝ´Ï´Ù.

# ±×³É Á¤¼ö¸¦ ÀÔ·ÂÇßÀ»¶§´Â ŸÀÔÀÌ Á¤¼ö(integer)ÀÓÀ» ¾Ë ¼ö ÀÖ½À´Ï´Ù.
a = 2
print(a,type(a))

# ¼Ò¼ýÁ¡À» Ãß°¡Çؼ­ ÀÔ·ÂÇØÁÖ¸é ±âº»ÀûÀ¸·Î ºÎµ¿¼Ò¼öÁ¡ ¼ö(floating point number)·Î ŸÀÔÀÌ ÁöÁ¤µË´Ï´Ù.
b = 2.0
print(b,type(b))

# ¹®ÀÚ¿­À» Á¤ÀÇÇϸé ÀÌ´Â ¹®ÀÚ¿­(string)À¸·Î ÁöÁ¤µË´Ï´Ù.
c = "Pytorch"
print(c,type(c))

# ¸¸¾à Á¤¼ö¿Í ºÎµ¿¼Ò¼öÁ¡ ¼ö¸¦ ´õÇÏ¸é ºÎµ¿¼Ò¼öÁ¡ ¼ö·Î ÀúÀåµË´Ï´Ù.
d = a+b
print(d,type(d))


# ¹®ÀÚ¿­³¢¸®´Â ´õÇϱ⠿¬»êÀ¸·Î ÀÌ¾î ºÙÀÌ´Â °ÍÀÌ °¡´ÉÇÕ´Ï´Ù.
e = str(a)+" "+c
print(e,type(e))

2 <class 'int'>
2.0 <class 'float'>
Pytorch <class 'str'>
4.0 <class 'float'>
2 Pytorch <class 'str'>

3. Arithmetic Operations

»çÄ¢¿¬»ê

In [4]:
# ÆÄÀ̽㿡¼­´Â ´Ù¾çÇÑ »çÄ¢¿¬»êÀÌ Á¤ÀǵǾî ÀÖ½À´Ï´Ù.

a=1
b=2
c=5

print(a+b)  # add
print(a-b)  # subtract
print(b*c)  # multiply
print(b/c)  # divide
print(c//b) # quotient
print(c%b)  # remainder
print(b**c) # power

3
-1
10
0.4
2
1
32

4. List

¸®½ºÆ®

In [5]:
# ¸®½ºÆ®ÀÇ »ý¼º
list_1 = [1,2,3]
print(list_1)

# ¸®½ºÆ®¿¡ ¿ä¼Ò Ãß°¡
list_1.append(4)
print(list_1)

# Á¤¼ö·Î¸¸ ÀÌ·ç¾îÁø ¸®½ºÆ®¿¡ ¹®ÀÚ¿­ Ãß°¡
list_1.append("abc")
print(list_1)

# ¸®½ºÆ®ÀÇ À妽Ì
print(list_1[2:-1])

# ¸®½ºÆ® ¿ä¼Ò Áö¿ì±â(delete)
del list_1[-1]
print(list_1)

# ¸®½ºÆ® ¸¶Áö¸· ¿ä¼Ò ²¨³»±â(pop)
list_1.pop()
print(list_1)

[1, 2, 3]
[1, 2, 3, 4]
[1, 2, 3, 4, 'abc']
[3, 4]
[1, 2, 3, 4]
[1, 2, 3]

5. Dictionary

µñ¼Å³Ê¸®

In [6]:
# µñ¼Å³Ê¸®ÀÇ »ý¼º
# "key" = value
dict_1 = {
    "python": 0,
    "java":1,
    "c++":2,
    "ruby":3,
    "html":4,
    "key":"value",
}

# µñ¼Å³Ê¸® Àüü¸¦ Ãâ·ÂÇÏ´Â ¹æ¹ý
print(dict_1)

# Å°¸¦ ÀÌ¿ëÇØ ±× Å°¿¡ ÇØ´çÇÏ´Â °ªÀ» ºÒ·¯¿À´Â ¹ý (call value by key)
print(dict_1["c++"])

# Å°¸¦ ÀÌ¿ëÇØ »èÁ¦ÇÏ´Â ¹æ¹ý (delete by key)
del dict_1["key"]
print(dict_1)

# µñ¼Å³Ê¸®¿¡ ¿ä¼Ò¸¦ Ãß°¡ÇÏ´Â ¹æ¹ý 
dict_1["pytorch"]=6
print(dict_1)

{'python': 0, 'java': 1, 'c++': 2, 'ruby': 3, 'html': 4, 'key': 'value'}
2
{'python': 0, 'java': 1, 'c++': 2, 'ruby': 3, 'html': 4}
{'python': 0, 'java': 1, 'c++': 2, 'ruby': 3, 'html': 4, 'pytorch': 6}

6. Loop

¹Ýº¹¹®

In [7]:
# range ÇÔ¼ö¸¦ ÀÌ¿ëÇÑ ±âº»ÀûÀÎ ¹Ýº¹¹®
for i in range(5):
    print(i)
print("\n")
    
# range ÇÔ¼ö´Â ½ÃÀÛÁ¡, ³¡Á¡, Çѹø¿¡ À̵¿ÇÏ´Â Å©±â¸¦ ÁöÁ¤ÇÒ ¼ö ÀÖ½À´Ï´Ù.
for i in range(0,-5,-1):
    print(i)

0
1
2
3
4


0
-1
-2
-3
-4
In [8]:
# ¸®½ºÆ®ÀÇ ¿ä¼ÒµéÀ» ÇϳªÇϳª¾¿ Ãâ·ÂÇÏ´Â ¹ý
print(list_1)
for i in list_1:
    print(i)
print("\n")

# µñ¼Å³Ê¸®ÀÇ key¿Í ÀÌ¿¡ ÇØ´çÇÏ´Â value¸¦ Ãâ·ÂÇÏ´Â ¹ý
print(dict_1)
for key in dict_1:
    print(key,dict_1[key])
print("\n")

# enumerate ÇÔ¼ö¸¦ »ç¿ëÇϸé ÇöÀç ¸î¹ø° Ãâ·ÂÀÎÁö È®ÀÎÀÌ °¡´ÉÇÕ´Ï´Ù.
for idx,i in enumerate(dict_1.keys()):
  print(idx,i)

[1, 2, 3]
1
2
3


{'python': 0, 'java': 1, 'c++': 2, 'ruby': 3, 'html': 4, 'pytorch': 6}
python 0
java 1
c++ 2
ruby 3
html 4
pytorch 6


0 python
1 java
2 c++
3 ruby
4 html
5 pytorch
In [9]:
# while ¹®À» ÀÌ¿ëÇÏ´Â ¹æ¹ý
a=0
while(a<10):
    print(a)
    a+=1

0
1
2
3
4
5
6
7
8
9

7. Condition

Á¶°Ç¹®

In [10]:
# ÀÏÄ¡ ¿©ºÎ Ãâ·Â
print(2==2)
print(2==3)

# ºÒÀÏÄ¡ ¿©ºÎ Ãâ·Â
print(2!=2)
print(2!=3)

True
False
False
True
In [11]:
# µñ¼Å³Ê¸®¿¡¼­ ruby¶ó´Â Å°¿¡ ÇØ´çÇÏ´Â value »Ì¾Æ³»±â

print(dict_1)

for key in dict_1:
    # key °ªÀÌ ÀÏÄ¡Çϸé ÇØ´ç Å°¿¡ ´ëÇÑ value¸¦ ÇÁ¸°Æ®ÇÕ´Ï´Ù.
    if key=="ruby":
        print(dict_1[key])
    # ÀÏÄ¡ÇÏÁö ¾Ê´Â °æ¿ì´Â µñ¼Å³Ê¸®ÀÇ ´ÙÀ½ key·Î ³Ñ¾î°©´Ï´Ù
    else:
        pass

{'python': 0, 'java': 1, 'c++': 2, 'ruby': 3, 'html': 4, 'pytorch': 6}
3
In [12]:
# À§ÀÇ ¹æ½ÄÀ» ÇÑÁٷΠǥÇö °¡´ÉÇÕ´Ï´Ù. ÀÌ´Â list comprehensionÀÇ ÇÑ ¿¹½ÃÀÔ´Ï´Ù.
[dict_1[key] for key in dict_1 if key=="ruby"]
Out[12]:
[3]

8. Function

ÇÔ¼ö¸¦ Á¤ÀÇÇÏ´Â ¹ý

In [13]:
# ´Ü¼øÇÑ ÆÑÅ丮¾ó ÇÔ¼ö¸¦ Á¤ÀÇÇÏ´Â ¿¹½Ã
def factorial(num):
    result = 1
    for i in range(1,num+1):
        result = result*i
    return result

print(factorial(5))

120

9. Class & Instance

In [14]:
# Ŭ·¡½ºÀÇ »ý¼º ¹× ÀνºÅϽºÈ­ ÇÏ´Â ¹æ¹ý
class Jedi(object):
    def __init__(self,name,droid):
        self.name = name
        self.droid = droid
        self.exp = 0
        
    def train(self):
        self.exp += 10

# instance 
anakin = Jedi("Anakin Skywalker","R2D2")
anakin.train()

print(anakin.name)
print(anakin.droid)
print(anakin.exp)

Anakin Skywalker
R2D2
10
In [ ]: