[python 기초] python의 String에 대하여

String

---

문자열

"~~"

'~~'

"""~~"""

- input()을 이용하면 string으로 저장되었었음

1. Raw String: 특수 부호

\n (next line)

\t (tab만큼 이동)

' 

"

r'o': 불가침 영역으로 인정

path = "c:\temp"
print(path) # c:    emp
 
# \를 이용
print("c:\\temp") # c:\temp
 
# \ escape sequence
path = 'c:\\program File\\python\\bin'
print(path) # c:\program File\python\bin
 
# r''이용
print(r'c:\program File\python\bin') #c:\program File\python\bin
 
#Let's go
# print(r'Let's go') # SyntaxError: invalid syntax
print("Let's go") # Let's go
print('"Here", she said') # "Here", she said

2. str()과 repr()

hello = 'Hello, world\n'
hello2 = repr(hello) 
 
print(hello) # Hello, world
             # (\n)
print(hello2) # 'Hello, world\n'
#다음줄로 넘어가지 말고, \n을 출력시켜라!

3. Formatted printing

print()에서 여러가지 사용이 가능하다.

for x in range(1,11):
    print(repr(x).rjust(2), repr(x*x).rjust(3), end='')
    print(repr(x*x*x).rjust(4))
    
#  1   1   1
#  2   4   8
#  3   9  27
#  4  16  64
#  5  25 125
#  6  36 216
#  7  49 343
#  8  64 512
#  9  81 729
# 10 1001000

for x in range(1,11):
    print(repr(x).rjust(2), repr(x*x).rjust(3), repr(x*x*x).rjust(4))
 
#  1   1    1
#  2   4    8
#  3   9   27
#  4  16   64
#  5  25  125
#  6  36  216
#  7  49  343
#  8  64  512
#  9  81  729
# 10 100 1000

for x in range(1, 11):
    print("\t",x, end='')
#     1     2     3     4     5     6     7     8     9     10    
 
for x in range(1, 11):
    print("\t", x)
#      1
#      2
#      3
#      4
#      5
#      6
#      7
#      8
#      9
#      10

4. String method

1) find

- 있으면 index값

- 없으면 -1 출력

subject = '$$$ Get rich now !!! $$$'
print(subject.find('$$$')) # 0
 
# find('word', start, end)
print(subject.find('$$$', 3)) # 21
print(subject.find('!!!', 0, 5)) # -1

2) join

- split -> join

- list로 분해되었던 아이들을 합칠때 이용함

*주의* 문자열에서만 사용가능하다.

# seq = [1, 2, 3, 4, 5]
# sep = '+'
# sep.join(seq) # TypeError: sequence item 0: expected str instance, int found
 
seq = ['1', '2', '3', '4', '5']
print('+'.join(seq)) # 1+2+3+4+5
sep = '+'
print(sep.join(seq)) # 1+2+3+4+5

window 경로지정할때 유용함 ㅋㅋㅋㅋㅋ

dirs = '', 'usr', 'bin', 'env'
print(dirs) # ('', 'usr', 'bin', 'env')
print('/'.join(dirs)) # /usr/bin/env
print('c:'+'\\'.join(dirs)) # c:\usr\bin\env

3) lower()

sen = "Think like a man of action and act like man of thought."
if 'think' in sen:
    print("sentence:",sen,'\nthink in sentence!')
else:
    print("sentence:",sen,'\nthink not in sentence!')
    # sentence: Think like a man of action and act like man of thought. 
    # think not in sentence!
    
sen = "Think like a man of action and act like man of thought."
if 'think' in sen.lower():
    print("sentence:",sen,'\nthink in sentence!')
    # sentence: Think like a man of action and act like man of thought. 
    # think in sentence!
else:
    print("sentence:",sen,'\nthink not in sentence!')

4) replace('before', 'after')

# replace
sen = 'This is a test'
print(sen.replace('is', 'was'))

5) split(default=' ')

# split (default =' ')
sen = 'This is a sentence'
print(sen.split(' ')) # ['This', 'is', 'a', 'sentence']
print(sen.split()) # ['This', 'is', 'a', 'sentence']
 
sen = '/usr/bin/env'
print(sen.split('/')) # ['', 'usr', 'bin', 'env']

6) strip(default=' ') 

양 끝의 공백 제거할때 사용

1 2 3 4 5

# strip() sen = '       ***internal        white space is not be***' print(sen.strip()) #***internal        white space is not be*** print(sen.strip(' ')) #***internal        white space is not be*** print(sen.strip('*')) #       ***internal        white space is not be

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