R中的程序结构（for,while,repeat）

1:5

for(i in 1:5) print(i)

ss <- seq(from=1, to=10, by=0.1)

for(s in ss) {
  print(s)
}

df = data.frame(
  age=c(21, 22, 23),
  name=c('KEN', 'John', 'JIMI'),
  stringsAsFactors = FALSE
);

#如果用in进行遍历data.frame，那么默认按列遍历
for(l in df) {
  print(l);
  print(l['age'])
  print(l['name'])
  print("---------------------")
}

for(i in 1:nrow(df)) {
  l <- df[i, ]
  print(l);
  print(l['age'])
  print(l['name'])
  print("---------------------")
}

i = 0
while(i<5) {
  i <- i+1;
  print(1:i);
}

i = 0
while(i<5) {
  i <- i+1
  if(i==4) {
    next;
  }
  print(1:i);
}

i = 0
while(TRUE) {
  i <- i+1
  if(i==4) {
    next;
  }
  print(1:i);
  if(i==10) {
    break;
  }
}

i = 0

repeat {
  i <- i+1
  if(i==4) {
    next;
  }
  print(1:i);
  if(i==10) {
    break;
  }
}