fixed indentation and import

Author: NoRaincheck

doc/source/comparison_with_r.rst

@@ -4,9 +4,8 @@
 .. ipython:: python
    :suppress:
 
-   from pandas import *
-   import numpy.random as random
-   from numpy import *
+   import pandas as pd
+   import numpy as np
    options.display.max_rows=15
 
 Comparison with R / R libraries
@@ -40,25 +39,25 @@ The :meth:`~pandas.DataFrame.query` method is similar to the base R ``subset``
 function. In R you might want to get the rows of a ``data.frame`` where one
 column's values are less than another column's values:
 
-    .. code-block:: r
+.. code-block:: r
 
-       df <- data.frame(a=rnorm(10), b=rnorm(10))
-       subset(df, a <= b)
-       df[df$a <= df$b,]  # note the comma
+   df <- data.frame(a=rnorm(10), b=rnorm(10))
+   subset(df, a <= b)
+   df[df$a <= df$b,]  # note the comma
 
 In ``pandas``, there are a few ways to perform subsetting. You can use
 :meth:`~pandas.DataFrame.query` or pass an expression as if it were an
 index/slice as well as standard boolean indexing:
 
-    .. ipython:: python
+.. ipython:: python
 
-       from pandas import DataFrame
-       from numpy.random import randn
+   from pandas import DataFrame
+   from numpy import random
 
-       df = DataFrame({'a': randn(10), 'b': randn(10)})
-       df.query('a <= b')
-       df[df.a <= df.b]
-       df.loc[df.a <= df.b]
+   df = DataFrame({'a': random.randn(10), 'b': random.randn(10)})
+   df.query('a <= b')
+   df[df.a <= df.b]
+   df.loc[df.a <= df.b]
 
 For more details and examples see :ref:`the query documentation
 <indexing.query>`.
@@ -72,20 +71,20 @@ For more details and examples see :ref:`the query documentation
 An expression using a data.frame called ``df`` in R with the columns ``a`` and
 ``b`` would be evaluated using ``with`` like so:
 
-    .. code-block:: r
+.. code-block:: r
 
-       df <- data.frame(a=rnorm(10), b=rnorm(10))
-       with(df, a + b)
-       df$a + df$b  # same as the previous expression
+   df <- data.frame(a=rnorm(10), b=rnorm(10))
+   with(df, a + b)
+   df$a + df$b  # same as the previous expression
 
 In ``pandas`` the equivalent expression, using the
 :meth:`~pandas.DataFrame.eval` method, would be:
 
-    .. ipython:: python
+.. ipython:: python
 
-       df = DataFrame({'a': randn(10), 'b': randn(10)})
-       df.eval('a + b')
-       df.a + df.b  # same as the previous expression
+   df = DataFrame({'a': random.randn(10), 'b': random.randn(10)})
+   df.eval('a + b')
+   df.a + df.b  # same as the previous expression
 
 In certain cases :meth:`~pandas.DataFrame.eval` will be much faster than
 evaluation in pure Python. For more details and examples see :ref:`the eval
@@ -123,38 +122,38 @@ summarize ``x`` by ``month``:
 
 
 
-    .. code-block:: r
+.. code-block:: r
 
-       require(plyr)
-       df <- data.frame(
-         x = runif(120, 1, 168),
-         y = runif(120, 7, 334),
-         z = runif(120, 1.7, 20.7),
-         month = rep(c(5,6,7,8),30),
-         week = sample(1:4, 120, TRUE)
-       )
+   require(plyr)
+   df <- data.frame(
+     x = runif(120, 1, 168),
+     y = runif(120, 7, 334),
+     z = runif(120, 1.7, 20.7),
+     month = rep(c(5,6,7,8),30),
+     week = sample(1:4, 120, TRUE)
+   )
 
-       ddply(df, .(month, week), summarize,
-             mean = round(mean(x), 2),
-             sd = round(sd(x), 2))
+   ddply(df, .(month, week), summarize,
+         mean = round(mean(x), 2),
+         sd = round(sd(x), 2))
 
 In ``pandas`` the equivalent expression, using the
 :meth:`~pandas.DataFrame.groupby` method, would be:
 
 
 
-    .. ipython:: python
+.. ipython:: python
 
-       df = DataFrame({
-           'x': random.uniform(1., 168., 120),
-           'y': random.uniform(7., 334., 120),
-           'z': random.uniform(1.7, 20.7, 120),
-           'month': [5,6,7,8]*30,
-           'week': random.randint(1,4, 120)
-       })
+   df = DataFrame({
+       'x': random.uniform(1., 168., 120),
+       'y': random.uniform(7., 334., 120),
+       'z': random.uniform(1.7, 20.7, 120),
+       'month': [5,6,7,8]*30,
+       'week': random.randint(1,4, 120)
+   })
 
-       grouped = df.groupby(['month','week'])
-       print grouped['x'].agg([mean, std])
+   grouped = df.groupby(['month','week'])
+   print grouped['x'].agg([np.mean, np.std])
 
 
 For more details and examples see :ref:`the groupby documentation
@@ -169,35 +168,36 @@ reshape / reshape2
 An expression using a 3 dimensional array called ``a`` in R where you want to
 melt it into a data.frame:
 
-    .. code-block:: r
+.. code-block:: r
 
-       a <- array(c(1:23, NA), c(2,3,4))
-       data.frame(melt(a))
+   a <- array(c(1:23, NA), c(2,3,4))
+   data.frame(melt(a))
 
 In Python, since ``a`` is a list, you can simply use list comprehension.
 
-    .. ipython:: python
-       a = array(range(1,24)+[NAN]).reshape(2,3,4)
-       DataFrame([tuple(list(x)+[val]) for x, val in ndenumerate(a)])
+.. ipython:: python
+
+   a = np.array(range(1,24)+[np.NAN]).reshape(2,3,4)
+   DataFrame([tuple(list(x)+[val]) for x, val in np.ndenumerate(a)])
 
 |meltlist|_
 ~~~~~~~~~~~~
 
 An expression using a list called ``a`` in R where you want to melt it
 into a data.frame:
 
-    .. code-block:: r
+.. code-block:: r
 
-       a <- as.list(c(1:4, NA))
-       data.frame(melt(a))
+   a <- as.list(c(1:4, NA))
+   data.frame(melt(a))
 
 In Python, this list would be a list of tuples, so
 :meth:`~pandas.DataFrame` method would convert it to a dataframe as required.
 
-    .. ipython:: python
+.. ipython:: python
 
-       a = list(enumerate(range(1,5)+[NAN]))
-       DataFrame(a)
+   a = list(enumerate(range(1,5)+[np.NAN]))
+   DataFrame(a)
 
 For more details and examples see :ref:`the Into to Data Structures
 documentation <basics.dataframe.from_items>`.
@@ -208,26 +208,26 @@ documentation <basics.dataframe.from_items>`.
 An expression using a data.frame called ``cheese`` in R where you want to
 reshape the data.frame:
 
-    .. code-block:: r
+.. code-block:: r
 
-       cheese <- data.frame(
-         first = c('John, Mary'),
-         last = c('Doe', 'Bo'),
-         height = c(5.5, 6.0),
-         weight = c(130, 150)
-       )
-       melt(cheese, id=c("first", "last"))
+   cheese <- data.frame(
+     first = c('John, Mary'),
+     last = c('Doe', 'Bo'),
+     height = c(5.5, 6.0),
+     weight = c(130, 150)
+   )
+   melt(cheese, id=c("first", "last"))
 
 In Python, the :meth:`~pandas.melt` method is the R equivalent:
 
-    .. ipython:: python
+.. ipython:: python
 
-       cheese = DataFrame({'first' : ['John', 'Mary'],
-                           'last' : ['Doe', 'Bo'],
-                           'height' : [5.5, 6.0],
-                           'weight' : [130, 150]})
-       melt(cheese, id_vars=['first', 'last'])
-       cheese.set_index(['first', 'last']).stack() # alternative way
+   cheese = DataFrame({'first' : ['John', 'Mary'],
+                       'last' : ['Doe', 'Bo'],
+                       'height' : [5.5, 6.0],
+                       'weight' : [130, 150]})
+   pd.melt(cheese, id_vars=['first', 'last'])
+   cheese.set_index(['first', 'last']).stack() # alternative way
 
 For more details and examples see :ref:`the reshaping documentation
 <reshaping.melt>`.
@@ -238,33 +238,33 @@ For more details and examples see :ref:`the reshaping documentation
 An expression using a data.frame called ``df`` in R to cast into a higher
 dimensional array:
 
-    .. code-block:: r
+.. code-block:: r
 
-       df <- data.frame(
-         x = runif(12, 1, 168),
-         y = runif(12, 7, 334),
-         z = runif(12, 1.7, 20.7),
-         month = rep(c(5,6,7),4),
-         week = rep(c(1,2), 6)
-       )
+   df <- data.frame(
+     x = runif(12, 1, 168),
+     y = runif(12, 7, 334),
+     z = runif(12, 1.7, 20.7),
+     month = rep(c(5,6,7),4),
+     week = rep(c(1,2), 6)
+   )
 
-       mdf <- melt(df, id=c("month", "week"))
-       acast(mdf, week ~ month ~ variable, mean)
+   mdf <- melt(df, id=c("month", "week"))
+   acast(mdf, week ~ month ~ variable, mean)
 
 In Python the best way is to make use of :meth:`~pandas.pivot_table`:
 
-    .. ipython:: python
-
-        df = DataFrame({
-            'x': random.uniform(1., 168., 12),
-            'y': random.uniform(7., 334., 12),
-            'z': random.uniform(1.7, 20.7, 12),
-            'month': [5,6,7]*4,
-            'week': [1,2]*6
-        })
-        mdf = melt(df, id_vars=['month', 'week'])
-        pivot_table(mdf, values='value', rows=['variable','week'],
-                    cols=['month'], aggfunc=mean)
+.. ipython:: python
+
+   df = DataFrame({
+        'x': random.uniform(1., 168., 12),
+        'y': random.uniform(7., 334., 12),
+        'z': random.uniform(1.7, 20.7, 12),
+        'month': [5,6,7]*4,
+        'week': [1,2]*6
+   })
+   mdf = pd.melt(df, id_vars=['month', 'week'])
+   pd.pivot_table(mdf, values='value', rows=['variable','week'],
+                    cols=['month'], aggfunc=np.mean)
 
 For more details and examples see :ref:`the reshaping documentation
 <reshaping.pivot>`.