DataFrame.md in red_amber-0.4.0

- old
+ new

@@ -55,10 +55,14 @@
 - from a `.arrow`, `.arrows`, `.csv`, `.csv.gz` or `.tsv` file
        
   ```ruby
   RedAmber::DataFrame.load("test/entity/with_header.csv")
   ```
+  
+  ```ruby
+  RedAmber::DataFrame.load("test/entity/without_header.csv", headers: [:x, :y, :z])
+  ```
 
 - from a string buffer
 
 - from a URI
 
@@ -273,10 +277,11 @@
 
 ### `tdr(limit = 10, tally: 5, elements: 5)`
 
   - Shows some information about self in a transposed style.
   - `tdr_str` returns same info as a String.
+  - `glimpse` is an alias. It is similar to dplyr's (or Polars's) `glimpse()`.
 
   ```ruby
   require 'red_amber'
   require 'datasets-arrow'
 
@@ -566,11 +571,11 @@
   # =>
   #<RedAmber::Vector(:uint8, size=3):0x000000000000f258>
   [1, 2, 3]
   ```
 
-### `slice  `  - slice and select records -
+### `slice  `  - cut into slices of records -
 
   Slice and select records (rows) to create a sub DataFrame.
 
   ![slice method image](doc/../image/dataframe/slice.png)
 
@@ -599,15 +604,18 @@
     9 Gentoo   Biscoe              49.9          16.1               213 ...     2009
     ```
 
 - Booleans as an argument
 
-  `slice(booleans)` accepts booleans as an argument in an Array, a Vector or an Arrow::BooleanArray . Booleans must be same length as `size`.
+  `filter(booleans)` or `slice(booleans)` accepts booleans as an argument in an Array, a Vector or an Arrow::BooleanArray . Booleans must be same length as `size`.
 
+  note: `slice(booleans)` is acceptable for orthogonality of `slice`/`remove`.
+
     ```ruby
     vector = penguins[:bill_length_mm]
-    penguins.slice(vector >= 40)
+    penguins.filter(vector >= 40)
+    # penguins.slice(vector >= 40) is also acceptable
 
     # =>
     #<RedAmber::DataFrame : 242 x 8 Vectors, 0x0000000000043d3c>
         species  island    bill_length_mm bill_depth_mm flipper_length_mm ...     year
         <string> <string>        <double>      <double>           <uint8> ... <uint16>
@@ -831,18 +839,18 @@
 
 ### `assign`
 
   Assign new or updated variables (columns) and create an updated DataFrame.
 
-  - Variables with new keys will append new columns from the right.
+  - Variables with new keys will append new columns from right.
   - Variables with exisiting keys will update corresponding vectors.
 
     ![assign method image](doc/../image/dataframe/assign.png)
 
 - Variables as arguments
 
-    `assign(key_pairs)` accepts pairs of key and values as parameters. `key_pairs` should be a Hash of `{key => array_like}` or an Array of Arrays like `[[key, array_like], ... ]`. `array_like` is ether `Vector`, `Array` or `Arrow::Array`.
+    `assign(key_value_pairs)` accepts pairs of key and values as parameters. `key_value_pairs` should be a Hash of `{key => array_like}` or an Array of Arrays like `[[key, array_like], ... ]`. `array_like` is ether `Vector`, `Array` or `Arrow::Array`.
 
     ```ruby
     df = RedAmber::DataFrame.new(
       name: %w[Yasuko Rui Hinata],
       age: [68, 49, 28])
@@ -855,16 +863,16 @@
     0 Yasuko        68
     1 Rui           49
     2 Hinata        28
 
     # update :age and add :brother
-    df.assign do
+    df.assign(
       {
         age: age + 29,
         brother: ['Santa', nil, 'Momotaro']
       }
-    end
+    )
 
     # =>
     #<RedAmber::DataFrame : 3 x 3 Vectors, 0x00000000000658b0>
       name         age brother
       <string> <uint8> <string>
@@ -930,11 +938,11 @@
   
   If assigner is empty or nil, returns self.
 
 - Append from left
 
-  `assign_left` method accepts the same parameters and block as `assign`, but append new columns from leftside.
+  `assign_left` method accepts the same parameters and block as `assign`, but append new columns from left.
 
   ```ruby
   df.assign_left(new_index: df.indices(1))
   
   # => 
@@ -1451,10 +1459,12 @@
     <string> <uint8>
   0 A              1
   1 B              4
   2 D              5
   ```
+##### `set_operable?(other)`
+  Check if `types` of self and other are same.
 
 ##### `intersect(other)`
 
   Select records appearing in both self and other.
 
@@ -1496,19 +1506,27 @@
   #<RedAmber::DataFrame : 1 x 2 Vectors, 0x0000000000029fcc>
     KEY1        KEY2
     <string> <uint8>
   1 B              2
   2 C              3
+
+  other.differencr(df)
+  #=>
+  #<RedAmber::DataFrame : 2 x 2 Vectors, 0x0000000000040e0c>
+    KEY1        KEY2                                    
+    <string> <uint8>                                    
+  0 B              4                      
+  1 D              5
   ```
 
 ## Binding
 
 ### `concatenate(other)`
 
-  Concatenate another DataFrame or Table onto the bottom of self. The shape and data type of other must be the same as self.
+  Concatenate another DataFrame or Table onto the bottom of self. The types  of other must be the same as self.
 
-  The alias is `concat`.
+  The alias is `concat` and `bind_rows`.
 
   An array of DataFrames or Tables is also acceptable as other.
 
   ```ruby
   df
@@ -1536,12 +1554,14 @@
   1       2 B
   2       3 C
   3       4 D
   ```
 
-### `merge(other)`
+### `merge(*other)`
 
-  Concatenate another DataFrame or Table onto the bottom of self. The shape and data type of other must be the same as self.
+  Concatenate another DataFrame or Table onto the bottom of self. The size of other must be the same as self. Self and other must not share the same key.
+
+  The alias is `bind_cols`.
 
   ```ruby
   df
   #=>
   #<RedAmber::DataFrame : 2 x 2 Vectors, 0x0000000000009150>