Finding Varianz einer Spalte von einem anderen angepassten Spaltenfaktor

Question

ich einen Datenrahmen in R haben die aus LOS und mehreren weiteren Bedingungen

LOS    Condition 
    1    Spinal 
    2    Urology 
    1    Thoracic 
    8    Spinal 
    5    Billary 
...     ... 

Ich möchte für jeden der breiteren die Varianz der LOS finden Bedingungen, gibt es einen einfachen Weg, dies zu tun?

Jeder Rat würde geschätzt werden, danke!

Reproduzierbare ähnlicher Datensatz unter

data <- structure(list(LOS = c(6, 6, 13, 6, 19, 7), Condition = structure(c(37L, 15L, 24L, 15L, 15L, 15L), .Label = c("Acute Liver Failure", "Aortic Disease", "Arthritis and Limb Deformity/Fractures", "Asphyxiation", "Billary", "Bowel Infection/Perforation/Infarction", "Breast Cancer", "Cancer (Unoperated)", "Cardiac Arrest", "Cardiac Arythmia", "Cerebral Aneurysm (Non-Ruptured)", "Cerebral Infarction", "Cerebral Oedema", "Chronic Liver Disease", "COPD/Asthma/Respiratory Failure", "Drug Overdose and Poisoning", "Ear/Nose/Throat", "Electrolyte", "Encephalitis", "Endocrine", "Epilepsy", "Gastroectomy", "Gynaecological Cancer/Surgery", "Heart Failure", "Hydrocephalus", "Hyperventilation Syndromes", "Infection incl. unspecified", "Influenza", "Interstitial Pulmonary Disease", "Large Bowel Cancer", "Max Fax Surgeries", "Meningitis", "Myocardial Infarction", "Neuro-Surgical Cancer", "Obesity", "Other Inter-Cerebral Haemmorhage", "Pancreatitis", "Perforation of Oesophagus", "Peripheral Vascular Disease (Inlc. Ischaemia and Infarction", "Pleural Effusion", "Pneumonia", "Psychiatric", "Pulmonary/Veno-Thrombo Embollism", "Skin Inflammation/Infection", "Skull and Facial Fractures", "Spinal Cord Weakness", "Spinal Surgery/Fractures", "Spinal Trauma", "Sub-Arachnoid Haemmorhage", "Systemic Weakness", "Thoracic/Abdominal Aortic Aneurysm (Non-Ruptured)", "Thoracic/Abdominal Aortic Aneurysm (Ruptured incl. injury)", "Trauma to Intra-Abdominal Organs/Vessels", "Trauma to Thoracic Cage", "Traumatic Inter-Cerebral Haemmorhage/Contusions/Oedema", "Urology/Renal Surgery" ), class = "factor")), .Names = c("LOS", "Condition"), row.names = c(NA, 6L), class = "data.frame")

Answer 1

Dies ist eine neues data.frame mit den Ergebnissen erstellt:

res <- data.frame(condition = factor(, levels = levels(data$Condition)), varLos = numeric(0)) 
for (i in unique(data$Condition)){ 
    res[nrow(res) + 1,] <- c(as.character(i), var(data[data$Condition == i, "LOS"], na.rm = T)) 
} 
res 
#       condition   varLos 
# 1     Pancreatitis    <NA> 
# 2 COPD/Asthma/Respiratory Failure 40.3333333333333 
# 3     Heart Failure    <NA> 

Die NA Werte eingeführt werden, da es nur keine Varianz mit einem Wert ist. Mit Ihrem Datensatz (der offensichtlich mehr Beobachtungen enthält) sollten diese nicht erstellt werden.