Using Branching Statements on entire list rather than individual items in R -

this follow-up question, though question here independent of one, using apply functions instead of , branching statements in r

i have data frame:

    date       close    weekday        dayofmonth 290 1991-02-22 365.65   friday         22 295 1991-03-01 370.47   friday          1 300 1991-03-08 374.95   friday          8 305 1991-03-15 373.59   friday         15 310 1991-03-22 367.48   friday         22 314 1991-03-28 375.22 thursday         28 319 1991-04-05 375.36   friday          5 324 1991-04-12 380.40   friday         12 329 1991-04-19 384.20   friday         19 334 1991-04-26 379.02   friday         26 339 1991-05-03 380.80   friday          3 

i want create column called weekofcycle figures out week of month given date in based on day of month. using function based on aforementioned question.

as.integer(cut(data$dayofmonth, c(-inf, 7, 14, 21, 28, inf))) 

the above line fridays, thursdays should

as.integer(cut(data$dayofmonth, c(-inf, 6, 13, 20, 27, inf))) 

desired output:

          date  close  weekday dayofmonth weekofcycle 290 1991-02-22 365.65   friday         22           4 295 1991-03-01 370.47   friday          1           1 300 1991-03-08 374.95   friday          8           2 305 1991-03-15 373.59   friday         15           3 310 1991-03-22 367.48   friday         22           4 314 1991-03-28 375.22 thursday         28           5 319 1991-04-05 375.36   friday          5           1 324 1991-04-12 380.40   friday         12           2 329 1991-04-19 384.20   friday         19           3 334 1991-04-26 379.02   friday         26           4 339 1991-05-03 380.80   friday          3           1 

i have tried work lapply function though doesn't work:

   data$weekofcycle <- with(data, lapply(weekday, function(i){                             if (i == "friday"){                                as.integer(cut(dayofmonth, c(-inf, 7, 14, 21, 28, inf)))                                }                             else if (i == "thursday"){                               as.integer(cut(dayofmonth, c(-inf, 6, 13, 20, 27, inf)))                             }                             }                            )) 

i feel close, missing something. ideally, i'd without if , else statement don't know how.

reproducible code data frame:

structure(list(date = structure(c(7722, 7729, 7736, 7743, 7750,  7756, 7764, 7771, 7778, 7785, 7792), class = "date"), close = c(365.65,  370.47, 374.95, 373.59, 367.48, 375.22, 375.36, 380.4, 384.2,  379.02, 380.8), weekday = c("friday", "friday", "friday", "friday",  "friday", "thursday", "friday", "friday", "friday", "friday",  "friday"), dayofmonth = c(22, 1, 8, 15, 22, 28, 5, 12, 19, 26,  3)), .names = c("date", "close", "weekday", "dayofmonth"), row.names = c(290l,  295l, 300l, 305l, 310l, 314l, 319l, 324l, 329l, 334l, 339l), class = "data.frame") 

thank help.

it if included desired output sample data can check whether i'm getting results desire, how method

#define shift each week day offset<-c(friday=0, thursday=1)  #see how may times 7 date of month monthweek <- unname((data$dayofmonth+offset[data$weekday]-1) %/% 7 +1)  cbind(data, monthweek) #           date  close  weekday dayofmonth monthweek # 290 1991-02-22 365.65   friday         22         4 # 295 1991-03-01 370.47   friday          1         1 # 300 1991-03-08 374.95   friday          8         2 # 305 1991-03-15 373.59   friday         15         3 # 310 1991-03-22 367.48   friday         22         4 # 314 1991-03-28 375.22 thursday         28         5 # 319 1991-04-05 375.36   friday          5         1 # 324 1991-04-12 380.40   friday         12         2 # 329 1991-04-19 384.20   friday         19         3 # 334 1991-04-26 379.02   friday         26         4 # 339 1991-05-03 380.80   friday          3         1 

in particular cases, there no need complicated if statements. can done pretty simple math.