R, Python 분석과 프로그래밍의 친구 (by R Friend)

  (1) if, elif, else 조건문을 사용한 FizzBuzz 코딩

# (1) if, elif, and else

for num in range(1, 31):

    if num % 3 == 0 and num % 5 == 0:

        print('FizzBuzz')

    elif num % 3 == 0:

        print('Fizz')

    elif num % 5 == 0:

        print('Buzz')

    else:

        print(num)

  (2) if, elif, else 조건문과 사용자 정의 함수(UDF)을 사용한 FizzBuzz 코딩

# (2) User Defined Function

def fizzbuzz(num):

    if num % 3 == 0 and num % 5 == 0:

        return 'FizzBuzz'

    elif num % 3 == 0:

        return 'Fizz'

    elif num % 5 == 0:

        return 'Buzz'

    else:

        return str(num)

print("\n".join(fizzbuzz(num) for num in range(1, 31)))

  (3) 문자열 합치기(Concatenating Strings)을 이용한 FizzBuzz 코딩

# (3) Concatenating Strings

for num in range(1, 31):

    string = ""

    if num % 3 == 0:

        string = string + "Fizz"

    if num % 5 == 0:

        string = string + "Buzz"

    if num % 5 != 0 and num % 3 != 0:

        string = string + str(num)

    print(string)

> rm(list=ls()) # clean all

# Sample vector

> set.seed(123) # for reproducibility

> vec_raw <- sample(c(0, 1), size=30, replace=TRUE, prob=(c(0.8, 0.2)))

> vec_raw

 [1] 0 0 0 1 1 0 0 1 0 0 1 0 0 0 0 1 0 0 0 1 1 0 0 1 0 0 0 0 0 0

> vec <- vec_raw # copy for manipulation

##---------------------------------------------

# Vector Bin Split by successive '0's criteria

##---------------------------------------------

# Setting

vec_tmp <- c() # null vector

bin_range <- 3 # successive '0's criterion

vec_idx <- 1

vec_num <- 1

# Zero_Bin_Splitter

while (length(vec) > 0){

  if (sum(vec[1:bin_range], na.rm=T) != 0){

    vec_tmp[vec_idx] <- vec[1]

    vec <- vec[-1]

    vec_idx <- vec_idx + 1

  } else if (is.null(vec_tmp)){

    assign(paste0("vec_split_", vec_num), vec[1:bin_range])

    vec <- vec[-(1:bin_range)]

    vec_idx <- 1 # initialization

    vec_num <- vec_num + 1

  } else {

    assign(paste0("vec_split_", vec_num), vec_tmp)

    vec_tmp <- c() # initialization

    vec_num <- vec_num + 1

    assign(paste0("vec_split_", vec_num), vec[1:bin_range])

    vec <- vec[-(1:bin_range)]

    vec_idx <- 1 # initialization

    vec_num <- vec_num + 1

  }

}

# delete temp vector and arguments

rm(vec, vec_tmp, bin_range, vec_idx, vec_num)

# by June Young Lee

library(data.table)

# 0이 세번 연속으로 들어 있는 아무 벡터 생성

vec <- c(0,0,0,3,10,2,3,0,4,0,0,0,1,2,50,4,0,0,32,1,0,0,0,1,1)

# data.table함수인 rleid이용하여 연속인 행들을 구분하는 idx1 컬럼 생성 

dt <- data.table(v1=vec, idx1=rleid(vec))

# idx1 기준으로 갯수를 세어 N 컬럼 생성 

dt[,N:=.N, by=idx1]

# 0이 세번 연속으로 나온 그룹(=N컬럼변수가 3인)을 idx2로 체크하기 

dt[v1==0&N==3,idx2:=1L]

# split 하기 위한 기준 벡터를 마찬가지로 rleid함수를 이용하여 idx3로 생성

dt[,idx3:=rleid(idx2)]

# data.table의 split 함수 적용하고, lapply 적용하여 v1 칼럼만 추출 

res <- lapply(split(dt, by="idx3"), function(x) x[,v1])

res

# $`1`

# [1] 0 0 0

# 

# $`2`

# [1] 3 10 2 3 0 4

# 

# $`3`

# [1] 0 0 0

# 

# $`4`

# [1] 1 2 50 4 0 0 32 1

# 

# $`5`

# [1] 0 0 0

# 

# $`6`

# [1] 1 1

# 0이 3번 연속으로 나온 놈들을 남겨두도록 작성한 이유는, 

# 위치확인 & 확인용입니다. 

# 필요없으면, 아래 정도의 코드를 추가하면 되겠네요.

res2 <- res[!unlist(lapply(res, function(x) length(x)==3&sum(x)==0))]

res2

# $`2`

# [1] 3 10 2 3 0 4

# 

# $`4`

# [1] 1 2 50 4 0 0 32 1

# 

# $`6`

# [1] 1 1

In [1]: a = 2 > 1

In [2]: a

Out[2]: True

In [3]: b = 2 < 1

In [4]: b

Out[4]: False

In [5]: type(a)

Out[5]: bool

 (1) 조건문에서의 참, 거짓 (True, False in Conditional statements)

# (1-1) Boolean False, True

In [6]: bool(False) # False

Out[6]: False

In [7]: bool(True) # True

Out[7]: True

# (1-2) None is False

In [8]: bool(None) # False

Out[8]: False

# (1-3) Number 0, 0.00 is False

In [9]: bool(0) # False

Out[9]: False

In [10]: bool(0.00) # False

Out[10]: False

In [11]: bool(5) # True

Out[11]: True

# (1-4) blank List [] is False

In [12]: bool([]) # False

Out[12]: False

In [13]: bool(['a', 'b']) # True

Out[13]: True

# (1-5) blank Tuple () is False

In [14]: bool(()) # False

Out[14]: False

In [15]: bool(('a', 'b')) # True

Out[15]: True

# (1-6) blank Dictionary {} is False

In [16]: bool({}) # False

Out[16]: False

In [17]: bool({'a': 'b'}) # True

Out[17]: True

  (2) 논리 연산자에서 참, 거짓 (True, False in Logical operators) : not, and, or

# (2-1) 피연산자 부정 'not' logical operator

In [18]: not True # False

Out[18]: False

In [19]: not False # True

Out[19]: True

In [20]: not 0 # True

Out[20]: True

In [21]: not 5 # False

Out[21]: False

In [22]: not None # True

Out[22]: True

In [23]: not '' # denial of blank String -> True

Out[23]: True

In [24]: not [] # denial of blank List -> True

Out[24]: True

In [25]: not () # denial of blank Tuple -> True

Out[25]: True

In [26]: not {} # denial of blank Dictionary -> True

Out[26]: True

In [27]: not 'ab' # False

Out[27]: False

In [28]: not ['a', 'b'] # False

Out[28]: False

In [29]: not ('a', 'b') # False

Out[29]: False

In [30]: not {'a' : 'b'} # False

Out[30]: False

In [31]: True and True # True

Out[31]: True

In [32]: True and False # False

Out[32]: False

In [33]: False and True # False

Out[33]: False

In [34]: False and False # False

Out[34]: False

In [35]: True or True # True

Out[35]: True

In [36]: True or False # True

Out[36]: True

In [37]: False or False # False

Out[37]: False

  (3) 비교 연산자에서의 참, 거짓 (True, False in Comparison operators) : ==, !=, >, >=, <, <=

# (3) Comparison(Relational) operators

In [39]: a = 1; b = 2; c = 2 # input data

# (3-1) == : If the values of two operands are equal, then the condition becomes true

In [40]: a == b # False

Out[40]: False

In [41]: b == c # True

Out[41]: True

In [42]: a != b # True

Out[42]: True

In [43]: b != c # False

Out[43]: False

In [39]: a = 1; b = 2; c = 2 # input data

# (3-3) > : If the value of left operand is greater than the value of right operand, 

# then condition becomes true

In [44]: a > b # False

Out[44]: False

In [45]: b > a # True

Out[45]: True

In [46]: b > c # False

Out[46]: False

In [39]: a = 1; b = 2; c = 2 # input data

# (3-4) >= : If the value of left operand is greater than or equal to the value of right operand, 

# then condition becomes true

In [47]: a >= b # False

Out[47]: False

In [48]: b >= a # True

Out[48]: True

In [49]: b >= c # True

Out[49]: True

In [39]: a = 1; b = 2; c = 2 # input data

# (3-5) < : If the value of left operand is less than the value of right operand, 

# then condition becomes true

In [50]: a < b # True

Out[50]: True

In [51]: b < a # False

Out[51]: False

In [52]: b < c # False

Out[52]: False

In [39]: a = 1; b = 2; c = 2 # input data

In [53]: a <= b # True

Out[53]: True

In [54]: b <= a # False

Out[54]: False

In [55]: b <= c # True

Out[55]: True